Nanotechnology in leukemia: diagnosis, efficient-targeted drug delivery, and clinical trials

There are four main forms of leukemia, including acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), and chronic myeloid leukemia (CML), which are listed in Table 1. Since complicated and distinct group of hematological neoplasms are involved in the diagnosis of leukemia, morphologic variations, cytogenetic anomalies, immunophenotype, and clinical characteristics could distinguish each type from the others [20].

The diagnosis of ALL involves cell morphology characterization by microscopy, immunophenotyping which is the gold standard for lineage assessment, classification, and detection of features that are important for the assessment of minimal residual disease. Chromosomal analysis with fluorescence in-situ hybridization or reverse transcription polymerase chain reaction (RT-PCR) is performed for the detection of selected genomic abnormalities, or recently in next generation sequencing have made possible whole genome sequencing [21]. In addition, AML diagnosis requires the identification of 20% or more myeloid blasts with morphological assessment of the peripheral blood or bone marrow. In addition, immunophenotyping by flow cytometry should be investigated to confirm the myeloid origin of malignant blast populations and to categorize the subtype of acute myeloid leukemia. Cytogenetic analysis and screening for the most common occurring gene mutations and rearrangements [22]. However, CLL diagnosis is determined by the presence of more than 5 × 10⁹/l monoclonal B lymphocytes in the peripheral blood. Using flow cytometry, the clonality of these B cells should be verified. Furthermore, the leukemia cells in the blood smear have the typical tiny, mature appearance of lymphocytes, a compact nucleus devoid of distinguishable nucleoli, and partially aggregated chromatin. They also have a limited border of cytoplasm [23]. Besides, the diagnosis of CML can be made using differential excessive agranulocytosis and a distinctive blood count. The detection of the Philadelphia chromosome, i.e., 22q- or BCR-ABL1 transcripts or both, in peripheral blood or bone-marrow cells may be conclusive for CML diagnosis [24].

Novel findings of chemotherapeutic agents, which are recognized as scientific and technological advance, allowed insights of cell biology of human cancer cells, and hence, targeted therapy has been applied. Granting the targeted therapy drugs with outstanding accomplishments in certain cancer cells, new therapies still cannot replace cytotoxic agents. Moreover, clinical trials have evidenced the combined effect of targeted molecules and traditional cytotoxic agents [40]. They are classified into alkylating agents (e.g., nitrogen mustards and its based hybrids) which are marketed as cyclophosphamide (Cytoxan^® or Neosar^®) [41].

Purine analogues as 6-mercaptopurine (6-MP) is one of the primary chemotherapeutic agents applied in acute leukemia, and still one of the most convenient drugs in maintenance therapy of ALL [42, 43]. It is marketed under the names Purinethol^® and Purixan^®. In addition, pyrimidine analogues are represented by cytarabine (1-β-D-arabinofuranosylcytosine; ara-C) T: Cytosar-U^®, Tarabine PFS^®. This drug has been approved by FDA and NCI for the management of ALL, CML and to prevent and treat meningeal leukemia. Its mechanism of action resides in the transportation of ara-C into the cell then it is phosphorylated into ara-C monophosphate (ara-CMP) by DCK and eventually to ara-C triphosphate (ara-CTP) which then contests with deoxycytidine triphosphate (dCTP) for incorporation into DNA and finally blocking DNA synthesis causing cell death [44].

Microtubule-target agents (MTA) have been also involved in the preservation of cell structure, protein transportation and mitosis. Vinca alkaloids are potential examples for this class. The most clinically important three alkaloids are vinblastine (VBL), vincristine (VCR), and vinorelbine (VRL) which have been approved in the United states by FDA [45]. Vinca alkaloids are recognized as destabilizing agents, where they depolarize microtubule, block the mitotic progression, and eventually lead to cell death by apoptosis [46]. VCR is marketed as Oncovin^® and Vincasar Pfs^® and commonly used in combination chemotherapy for treating pediatric leukemia.

Leukemia patients are treated with antibiotics (e.g., anthracyclines and anthracenediones), as one of the main classes of chemotherapeutic drugs. Two anthracyclines for AML, daunorubicin (DD) (Cerubidine^®) and idarubicin (IDA) (idamycin PFS^®), are thought to work by forming complexes with DNA through base pair intercalation and inhibiting topoisomerase II activity by stabilizing the DNA–topoisomerase II complex, which stops topoisomerase II from catalyzing the ligation–relegation reaction. Idarubicin may also damage DNA by free radical damage, disrupt the control of gene expression, and limit polymerase activity. Furthermore, it was stated that idarubicin outperformed daunorubicin in terms of intracellular accumulation and DNA binding ability [47, 48]. Besides, mitoxantrone (e.g., Novantrone^®, Mitozantrone^®) belong to anthracenediones class and has been approved for use in AML [49]. Notably, compared to anthracyclines, mitoxantrone showed reduced cardiac toxicity because of its lower generation of quinone-type free radicals.

CD3 + CD4–CD8–double negative T cells (DNTs) are immune cells that produce substantial cytotoxicity in many tumor cells in a nonspecific manner. As a result, they have emerged as functional immune cells in the field of anticancer therapy [50]. The AML resistance to chemotherapy, which ultimately results in recurrence and death, is one of the main problems with conventional chemotherapeutic drugs. To enhance the anti-leukemic effects of conventional chemotherapy and target diseases resistant to chemotherapy, a combination of DNT therapy and chemotherapy was proposed as an alternate treatment. Ara-C and daunorubicin (DNR) were used in combination with DNT in xenograft model, results revealed that the efficacy of combining an adoptive T-cell therapy and low-dose chemotherapy in reducing therapy-resistant AML. These findings suggested utilizing DNTs as an adjuvant cellular therapy following administration of chemotherapy [51].

Imatinib (Gleevec^®) is a competitive pyridine-based inhibitor interfering with the ATP binding site, including tyrosine kinase, and hence, it is also classified among tyrosine kinase inhibitor (TKI) [52]. This mechanism has qualified imatinib as a drug of choice for the treatment for CML that is evidenced by improvement in patients with CML, though it has limitations, including the inability to eradicate CML primitive progenitors, which resulted in the elevation of the relapse rate when imatinib is withdrawn. On the other hand, interferon-α (IFN-α) (e.g., Intron^®-A or Roferon^®-A) directly targets CML stem cells by inducing cytogenetic remission. Consequently, patients treated with IFN-α were able to sustain durable remissions after discontinuing therapy. Nevertheless, the side effects of IFN-α hinder its administration as well as its cost was 200 times those of the conventional therapy [53]. Furthermore, clinical studies suggested that the combination of imatinib and IFN-α is superior to either therapy, due to their different mechanisms of action [54].

Radiation therapy (RD) may be used to eradicate leukemia cells or relieve pain from swollen lymph nodes, the spleen, or the liver. It is also a promising treatment for bone pain brought on by leukemia cells growing in the bone marrow. Low doses of RD may also be administered before stem cell transplantation. It includes external beam radiation therapy (EBRT), total body irradiation (TBI), and total marrow irradiation (TMI) [55]. Because lymphocyte cells are extremely sensitive to radiation, adding RD to systemic therapy has been reported to be effectively used for leukemia treatment. Therefore, use of RD is a well-established regimen prior to allogeneic stem cell transplantation [56].

Traditional detection techniques have certain drawbacks, like being expensive, time-consuming, and labour-intensive. They are not suitable for simple and quick medical monitoring or analysis, since they need a complex combination of equipment, have low sensitivity, and require multiple processing stages. Thus, modern diagnostic tools have been investigated to create cutting-edge tactics in response to the need for the development of improved diagnostic and therapeutic approaches with the highest level of specificity, efficiency, and minimal toxicity [61]. Therefore, rapid, sensitive, easy-to-use, and reasonably priced instruments are becoming more and more necessary for the diagnosis of leukaemia. These tools should not only enable correct diagnosis but also help doctors choose the best course of treatment. Karyotyping, immunophenotyping by flow cytometry or microarray, which combines bone marrow and peripheral blood cytochemical tests, and PCR-based techniques—which are costly and involve numerous steps—are among the diagnostic methods for leukaemia [65]. In this context, NPs have demonstrated their ability to offer substitute approaches to these challenges by offering quick, secure, and precise leukaemia diagnosis techniques.

Specific aptamers which bind to specific target molecules have been widely exploited loading on NPs for detection of leukaemia cells has been applied by many researchers due to their specificity of targeting the desired cells based on loading the NPs with specific targeting molecules with negligible cytotoxicity [63, 66]. One example is Sgc8 aptamer which has been employed in studies because of its selectivity to leukaemia cell. Tan, et al. utilized a simple method to detect leukaemia based on amine-labelled Sgc8 aptamer-modified fluorescent silica NPs (FSNPs) prepared via amide coupling between amino and carboxyl groups which detected leukaemia cells with high accuracy and sensitivity assessed by flow cytometry and fluorescence microscopy. Sgc8-specific targeting combined with FSNPs' showed stronger fluorescence intensity and photostability, and thus, it may provide a clinically valuable tool for early diagnosis and prompt treatment [67]. In addition, Khoshfetrat et al. used thiolated Sgc8c aptamer immobilized on gold NPs-coated magnetic Fe₃O₄ NPs (Apt-GMNPs) with a hairpin structure to form Aptasensors and intercalating Ethidium bromide (EB) for the quantification of the leukaemia cells. When leukaemia cancer cells are introduced onto the Aptasensors, the hairpin structure of the aptamer is disrupted and the intercalated molecules are released, resulting in a decrease of the electrochemical signal which is detected. This new diagnostic tool showed a linear response and was successful in detection of leukaemia cancer cells in complex media, such as plasma, without significant interference [68].

Grechkin et al. also utilized Sgc8-aptamer conjugated with amino- and carboxyl-modified silica-coated terbium (III) thiacalix arenesulfonate to form luminescent NPs that were able to detect leukaemia cells using fluorescence microscopy without induction of cell apoptosis or necrosis, which can be common in bioimaging applications. At this experiment, CCRF–CEM (human T lymphoblasts cell line) and Jurkat cells (an immortalized line of human T lymphocyte) were investigated as models. The findings indicated that CCRF–CEM had a larger shift in fluorescence intensity than Jurkat cells, which may be related to the latter's lower concentration of a tyrosine protein kinase 7 (PTK7) on the cellular membrane [69].

The labelling of NPs or receptor ligands by fluorescent markers is a well-established method for cancer diagnosis as well as the identification of cell phenotype. Maclaughlin et al. harnessed this strategy by developing an antibody-targeted, PEG-coated surface-enhanced Raman scattering (SERS) gold NPs (AuNPS) which can be used to label three cell surface markers on cancerous B cells from the LY10 lymphoma cell line. Using confocal Raman mapping and SERS from cell suspensions, the specificity of the particles' cell labelling was shown on primary CLL and LY10 cells, respectively. The results were also confirmed through the flow cytometer which was used to validate the binding of SERS probes to LY10 over vast cell populations [70]. Moreover, Haghighi et al. combined fluorescent gold nanoclusters (GNCs) with a super paramagnetic (Fe₃O₄/GNCs) nanoprobe for imaging and detection of human leukaemia cancer cells (HL-60) using (γ-Mercaptopropyl) trimethoxysilane (MPS) as a stabilizer decorated with the thiol-modified KH1C12 aptamer. The aptamer-functionalized Fe₃O₄/GNCs nanoprobe proved its ability to uptake and -image HL-60 cancer cells as well as detection of cancer cells from a range of concentrations 10–200 cells μL⁻¹ which can help in early diagnosis of lekemia. The nanoprobe's magnetic and fluorescent properties are particularly significant for MRI-based fluorescence imaging and the collection of HL-60 cancer cells, which may aid in the early detection of extremely aggressive human leukaemia [71]. Asides, AuNPS were fabricated as biosensors by Ensafi et al. by modification of a gold electrode with AuNPS coated with ZAP70 oligonucleotide probe to detect specific sequence of ZAP70 gene, which is a predictor of the IgVH mutation status and serve as prognostic indicator for distinguishing Ig-mutated from Ig-unmutated CLL. The biosensor can detect with a detection limit ZAP70 DNA sequence of 4.0 × 10⁻¹⁵molL⁻¹ and a decent calibration range between 2.0 × 10^–14 and 1.0 × 10⁻⁹molL⁻¹. This biosensor is thought to be the most informative stage-independent prognostic indicator for CLL patients [72]. Another application of AuNPS was done by Mazloum-Ardakani et al. to synthesize a stable composite with electrical properties, on the surface of a biosensor by synthesizing poly (catechol) with enhanced conducting properties by modification with graphene sheets and loading on AuNPS, i.e., made up of conductive polymers and nanoparticles. With a detection limit of 1.0 pM for the DNA strand, the peak currents of the electroactive probe catechol were linearly correlated with the logarithm of the target DNA concentrations in the range of 100.0 μM to 10.0 pM. This study looked into a novel, stable composite that was used to identify AML [73].

Furthermore, Bordbar et al. utilized a different and simple technique by employing volatile organic compounds (VOCs) in blood samples as biomarkers to diagnose leukemia based on a paper-based sensor array for detecting leukemia which contains 16 NPs deposited on a sheet of hydrophobic paper in a 4 × 4 array format. The diagnosis was made by comparing the image of sensors recorded by a scanner before and after exposing to the blood vapour. The accuracy of the rock curve in differentiating patients from the control group was 96%. According to the logistic regression model, this approach properly categorised 93.6% of healthy individuals and 93.2% of patients. In addition, for every 20 units rise in overall response, the likelihood of being classified as a patient fell by 10%. With improved sensitivity and specificity, it is a low-cost, non-invasive method of identifying new leukaemia cases [74]. Recently, Wang et al. have reviewed the use of iron oxides NPs which have gained increasing attention in diagnosis and treatment of leukemia. The ability to detect magnetic resonance imaging (MRI) as effective contrast agents, magnetic biosensors, and targeted administration of anti-leukemia medications by coating various targeting moieties are among the benefits of iron oxide nanoparticles [75].

The application of NPs and nanocarriers has improved the delivery of chemotherapeutic agents, primarily to lessen their toxicity to normal tissue. Other benefits include improving the bioavailability, reducing side effects, solubility, blood circulation time. In addition, anti-tumor drug candidates were found to be improved by nano-delivery systems, which also use targeting or sensing techniques to release medications selectively at specific locations [61, 64, 76]. The same is true for anti-leukemia drugs, which is why many research have looked into different ways to distribute them using nanocarriers.

Polymeric NPs are one example of nanocarriers widely used by researchers for loading of drugs due to their versatility and potential low toxicity [77]. Simon et al. loaded all-trans retinoic acid (ATRA) in poly-D, L-lactadie-co-glycolide (PLGA) polymeric NPs for treatment of acute promyelocytic leukemia. This strategy allowed ATRA to be administered intravenously instead of orally which is valuable for patients who have difficulties in swallowing, which is common in case for leukemia patients [78]. PLGA was also utilized by Leung et al. for encapsulation of curcumin (Cur-PLGA NP) using a microfluidic-assisted nano-precipitation surfactant free technique that showed excellent colloidal and drug stability as well as a dose-dependent cytotoxicity in leukemia Jurkat cells without altering the viability of fibroblast NIH3T3 cells [79]. Hasandoost et al. prepared imatinib mesylate-loaded polybutylcyanoacrylate (PBCA) NPs which enhanced the cytotoxic effects of imatinib mesylate compared to free drug alone. The miniemulsion polymerization process was used to create the formulation demonstrating that the drugs were physically entrapped by nanoscale particles with a high encapsulation efficiency of 86% [80].

Combined therapy is often used in leukemia treatment to avoid resistance to treatment. Cortese et al. research team focused on this strategy and benefited from NPs ability to load several drug molecules by formulating a poly (ε-caprolactone) (PCL) system with biodegradable pH-sensitive core for nilotinib release and an enzymatic sensitive outer shell for imatinib release which allowed for combined therapy of both drugs. This system showed better cytotoxicity to leukemia cells compared to free drug [81]. The same team used the PCL loaded NPs with imatinib in combination with doxorubicin loaded sensitive polyelectrolyte complexes (PECs) which allowed a down-regulation of BCR–ABL in a sustained manner as well as significant CML stem cell death as both drugs worked in a synergistic manner with maximized cytotoxicity with minimized probability of cell resistance to any of these drugs [82]. The same research team also utilized PCL NPs to encapsulate RNA–protamine complex encapsulated for the intracellular delivery of mRNA molecules. These NPs had a core–shell structure with an mRNA-containing inner core surrounded by PCL layers which increased the in vivo stability of the mRNA and allowing their efficient delivery [83].

The loading of SiRNA was attempted by Valencia-Serna et al. using lipopolymers, namely, α-linolenic acid (ALA) substitution on low molecular weight polyethyleneimine (PEI) to deliver specific siRNAs to CML cells for therapeutic gene silencing of BCR–ABL gene. The results showed that siRNA/PEI–ALA NPs successfully allowed the silencing of the BCR–ABL gene and BCR–ABL protein, thereby decreasing the growth on CML K562 cells in vitro and arresting the growth of localized tumors in a CML mouse model [84].

Inorganic NPs have been widely exploited as nanocarriers for leading of ant-leukemic drugs. Mesoporous silica NPs were coated with folic acid PEG–lipid bilayer membrane loaded with paclitaxel and tanshinone by Li et al. It allowed a sustained release of both drugs with enhanced uptake of the NPs by NB4 cells due to the presence of folic acid leading to targeting of folic acid receptors on NB4 cells [85]. Drug resistance was diminished by Deng et al. through combined delivery of AS1411, doxorubicin and anti-221 via multifunctional AuNPS which significantly decreased the proliferation and clonogenic potential as well as facilitating the apoptosis of drug resistant leukemia cells. These systems also showed marked down regulation of miR-221 and DNMT1, leading to restoring the expression of p27kip1 and p15ink4b tumor suppressors as well as miR-221-mediated decrease of P-glycoprotein (P-gp) expression thereby providing a more efficient treatment [86]. AuNPS were also utilized by Petrushev et al. to conjugate TKIs that inhibit FLT3 kinase thereby targeting the FLT#3 mutation causing relapse in AML patients. The new prepared bioconjugate had better therapeutic effect that TKI alone as well as effective trans-membrane delivery [87].

Carbon-based NPs have been utilized due to their biocompatibility and high loading efficiencies. Shahiri.et al. synthesized multi-walled carbon nanotubes (MWCNTs) coated with silver NPs (Ag-NPs) which showed efficacy as antioxidant and cytotoxic agents against AML and acute T-cell leukemia cell lines in a dose depended manner [88]. Moreover, Felix et al. formulated imatinib loaded quantum dots, which graphene NPs are known for their safety and internalization efficiency in the cells. The results of this research confirmed the ability of the quantum dots loaded with Imatinib to sufficiently internalize and induce apoptosis and killing of cancer cells [89]. Quantum dots were also used by Esmaeili et al. as zinc oxide quantum dot NPs (ZnO QD NPs) as nanofluid (NF) to treat acute promyelocytic leukemia (APL)-derived NB4 cells. The resultant NPs successfully lowered the proliferation of NB4 cells through p21-mediated G1 cell cycle arrest and enabled their apoptosis via reactive oxygen species (ROS)-dependent up regulation of FoxO3a and SIRT1 as well as peroxisome proliferator-activated receptors gamma (PPARγ) up regulation in NB4 cells leading to elevated expression of pro-apoptotic molecules in NB4 cells [90].

Furthermore, Anu et al. synthesized selenium nanoparticles (SeNPs) as green biogenesis NPs from Cassia auriculata and shown their effectiveness against leukemia cancer cells in vitro, as well as greater solubility and decreased toxicity on normal cells [91]. Niosomal formulations to encapsulate ifosfamide, alkylating anticancer drug, was developed to control its release and alleviate its toxicity [92]. Nanocarriers for efficient delivery of anti-leukemia drugs are summarized in Table 2.

Several efforts have focused on the development of approaches that allowed targeted delivery of chemotherapeutic drugs as most of these drugs lack selectivity which cause major side-effects as well as lower effectiveness in many patients. Thus, the need arises to smart drug formulations that deliver the drugs selectively to cancer cells, thereby enhancing drug efficacy and reducing nonspecific cytotoxic effects to normal cells [59, 94]. The novel and emerging NPs for targeted treatment of leukemia are summarized in Table 3.

One strategy of targeting is to prepare or coat the NPs with a specific target for an over-expressed receptor on a cancer cell. Sun et al. developed curcumin loaded hyaluronic acid-modified liposomes (HA-Cur-LPs) which targeted the CD44 receptor and consequently curcumin is targeted to these cells with high stability as CD44 is overexpressed on the surface of leukemia cells. HA-Cur-LPs also provided mice with longer survival time compared to free curcumin treatment [95]. Hyaluronic acid was also utilized by Zhang et al. through formulating hyaluronic acid-coated AgNPs (HA-AgNPs) via electrostatic interaction between the negatively charged HA molecules and positively charged AgNPs which exert their anti-leukemic action through ROS overproduction thereby inhibited the leukemia cells viability by specific binding of HA with CD44 receptors causing apoptosis while having decreased systemic toxicity [96].

Mesoporous silica NPs were used by Durfee et al. used to form a template surrounded by a liposome layer on them to form Protocells. These Protocells were then coated with antibiotic protein combined with biotinylated EGFR antibody. The prepared NPs-targeted leukemia cells efficiently as well as offering a targeted release of gemcitabine which prevented proliferation of myeloid leukemia stem cells and induced apoptosis [97].

Davis et al. loaded leukemia inhibitory factor (LIF) on poly (ethylene glycol)–poly (lactic acid) (PEG–PLA) NPs (NanoLIF) then modified their surface with CD11b antibody to target activated peripheral macrophage. The resultant NPs significantly decreased M1 cell proliferation over 72 h compared to free LIF [98].

Another strategy is oligopeptides and oligonucleotides which can be synthesized to target specific biomarkers or even synthesize personalized drugs for individual patients. Zhao et al. formulated an oligonucleotide single-strand DNA aptamer for targeting CD117 biomarker, which is over expressed on AML cells. Furthermore, they also designed an aptamer − methotrexate complex which could target primary AML cells without affecting the background marrow cells [99]. Fan et al. synthesized a double oligopeptide coupled NPs for targeting of osteoblastic and vascular niches in bone marrow. The prepared NPs also enhanced the stability and loading efficiency of Arsenic trioxide and targeted it to the cancer lesions eliminating primitive CML cells as well as improving arsenic trioxide protection to the original CML cells, and reducing the size of the K562–HUVEC organoid [100].

RNA-based therapies were exploited for treatment of leukemia as they can silence gene expression, express proteins, edit genes, thereby serving as a tailored treatment for specific types of leukemia; however, they suffer from poor in vivo stability and thus need to be encapsulated in NPs which have the stealth ability thereby preserving them from degradation [59]. Lee et al. loaded siRNA polyplexes on folate–PEG oligoaminoamide that protected siRNA against degradation as well as targeted its delivery to leukemia cells as it has folic acid receptor over expression. [101]. Lui et al. targeted a CRISPR/Cas9 system for treatment of CML by encapsulating a CRISPR/Cas9 plasmid (pCas9) which expresses gRNA to target the BCR–ABL gene (pCas9/gBCR–ABL) with poly(ethylene glycol)-b-poly(lactic acid-co-glycolic acid) (PEG–PLGA)-based cationic lipid-assisted polymeric NPs (CLANs). The prepared NPs were able to disrupt the CML-related BCR–ABL gene without affecting the same gene in normal cells thereby improving the survival rate in a CML mouse model [102]. AuNPS decorated with an antisense oligonucleotide were used for silencing the BCR–ABL1 chimeric gene and enhancing leukemia cell apoptosis significantly with loss of viability of imatinib-resistant K562 cells [103]. Exosomes are natural vesicles secreted by cells were utilized by Min et al. through extracting exosomes from imatinib-resistant CML cells and using them as vectors to deliver miR-365. Successful uptake of exosomes CML cells was achieved as well as successful targeted receptors on target cells, thereby accumulating miRNA in target tissues [104].

Cyclodextrin NPs were synthesized by Guo et al. and decorated with FAB antibody to target AML which specifically targets human leukemia stem cells (LSC) surface antigen IL-3 receptor α-chain. Furthermore, it had a synergistic therapeutic effect when combined the drug ara-C [105]. Dai et al. developed transferrin paclitaxel loaded lipid NPs (TPLN) which showed enhanced targeting to the HL-60 cancer cells compared to that of the paclitaxel-loaded NPs (PLN) due to the ability of transferrin to target leukemia cells leading to remarkable apoptosis of leukemia cells [106].

Abdellatif et al. utilized quantum dots, a form of carbon-based NPs to formulate amino-PEGylated quantum dots (QDs) which were succinylated using succinic anhydride and coated with octreotide (QD–OCD) to target somatostatin receptor type-II (SSTR) which is expressed in leukemia cells. QD–OCD accumulated in blood cells indicated by their fluorescence intensity due to SSTR targeting thereby showing potential for leukemia treatment [107]. In addition, Nui et al. synthesized a fluorescent lanthanide oxyfluoride nanoparticle-based multifunctional peptide drug delivery system for AML treatment via targeting mouse double minute 2 (MDM2) and/or MDMX by a dodecameric peptide antagonist (PMI) and an overexpressed cell surface receptor, CD33 through humanized monoclonal antibody. The resultant nanoparticle had no toxicity on normal cells and enabled apoptosis induction of AML cell lines and primary leukemic cells. An additional advantage of the prepared NPs is their fluorescence which facilitated real-time visualization of apoptotic events in AML cells, which is useful in tracking the response and treatment efficiency [108].

Finally, inflammation and bacterial oral infection may accompany and worsen the case of leukemia patients as a result of chemotherapy and immunosuppression. A bimetallic clusterzyme was created by Pt atom replacement in the structure of gold nanocluster (Au/Pt NCs) coupled with glucose oxidase (GOX) Au/Pt NCs@GOX). The in vivo investigations demonstrated that it is possible to successfully cure periodontitis in rats, and enhance periodontal tissue regeneration [109]. In addition, a modified photocross-linkable gelatin-based polymer (GelMA) containing cationic quaternary ammonium salt groups may be helpful in preventing accompanied infections [110]. The associated coagulation and hemostasis problems should be investigated by synthesis of biocompatible anticoagulant and hemostatic materials through surface-functionalized designs [111].

Using carefully designed materials to create innovative treatments and devices that may lessen toxicity while improving treatment delivery and efficacy is known as nanotechnology in oncology. Notably, the most well-known nano-based medications, Abraxane^® and Doxil^®, were approved by the FDA a few years ago and have since been effectively employed in clinical settings. Currently, various nano delivery systems have undergone experimental stage and animal models. However, many factors need to be established before its successful clinical applications on humans, such as clearance, long-term toxicity, biocompatibility, selectivity, immunogenicity, pharmacokinetics and bio distribution which still lake sufficient data [112]. Nevertheless, many NPs drug products have gone successfully through clinical trials or even gained approval for marketing.

One example is Vyxeos^® by Jazz pharmaceuticals which obtained FDA approval in 2017 which is a liposome injection loaded with daunorubicin and ara-C. This drug product utilized the advantage of loading several drugs in the same carrier or vesicle, offering the advantage of combined therapy which is beneficial for treatment of leukemia compared to a single drug therapy and consequently offered a significantly increased survival rate [113]. Marqibo^® is another FDA approved drug product comprising sphingomyelin and cholesterol liposome NPs loaded with VCR. The formulations aim to eliminate the limitations of dosing and pharmacokinetics of conventional VCR drug products in addition to increase the circulation time, optimized delivery to target tissues and enhanced dosing concentrations without increasing toxicity. In addition, patients treated weekly with this new formula achieved complete remission of 20% with an overall response rate of 35%. This new formulation also counteracted the dose-dependent toxicity of VCR administration, such as neuropathy [114].

According to clinicaltrials.gov, current clinical trials involve a study done in University Hospital Zurich, Switzerland for the use of magnetic NPs, coated with epithelial cell adhesion molecule (EpCAM)–antibodies to target epithelial tumor cells. The study aims to see if circulating tumor cells (EpCAM or CD52 as marker) can be removed out of the blood with the help of these particles for the aim of leukemia diagnosis. Another study is conducted by AstraZeneca in phase I/II to determine the maximum tolerated dose as well as the safety, pharmacokinetics, and pharmacodynamics of AZD2811 NPs either as single therapy or in combination with other drugs for treatment of relapsed/refractory AML patients or for treatment of naïve AML patients who are not eligible for intensive induction therapy.

Currently in phase I, Memorial Sloan Kettering Cancer Centre in collaboration with National Cancer Institute (NCI) and Actinium Pharmaceuticals are conducting a clinical study on Targeted Atomic Nano-Generators (Actinium-225-Labeled Humanized Anti-CD33 Monoclonal Antibody HuM195) to determine the safety and dosing of actinium-225 when it is labelled to HuM195. The medication is acknowledged as a clinical-stage radioimmunotherapy that targets CD33 and has demonstrated single-agent activity in AML treatment. The result of this research revealed that its combination with venetoclax is a potential candidate for the treatment of patients with venetoclax-resistant AML [115].

A phase I study by Mayo clinic and national cancer institute currently investigates the safe therapeutic doses as well as the adverse effects of paclitaxel albumin–nanoparticle formulation (nab-paclitaxel) and rituximab-coated nanoparticle for treatment of unresponsive or relapsing B-cell non-Hodgkin lymphoma (NHL) in patients.

Despite of the significant advancements in the field of nanomedicine, the potential harmful effects of nanomaterials on humans remain a source for concern. Significant studies have been performed in recent years to try to understand these harmful effects, and as a result of cellular exposure to nanomaterials, a number of pathways, mechanisms, and important influencing parameters have been linked. The immunological changes brought on by these nanoparticles have also been clarified by these assessments of nanotoxicology. Understanding the process by which nanomaterials trigger immunological responses is necessary to regulate the immunomodulatory effect of these materials in applications [116].