Leukocyte-Repelling Biomimetic Immunomagnetic Nanoplatform for High-Performance Circulating Tumor Cells Isolation

Macrophage based drug delivery: Key challenges and strategies

As a natural immune cell and antigen presenting cell, macrophages have been studied and engineered to treat human diseases. Macrophages are well-suited for use as drug carriers because of their biological characteristics, such as excellent biocompatibility, long circulation, intrinsic inflammatory homing and phagocytosis. Meanwhile, macrophages' uniquely high plasticity and easy re-education polarization facilitates their use as part of efficacious therapeutics for the treatment of inflammatory diseases or tumors. Although recent studies have demonstrated promising advances in macrophage-based drug delivery, several challenges currently hinder further improvement of therapeutic effect and clinical application. This article focuses on the main challenges of utilizing macrophage-based drug delivery, from the selection of macrophage sources, drug loading, and maintenance of macrophage phenotypes, to drug migration and release at target sites. In addition, corresponding strategies and insights related to these challenges are described. Finally, we also provide perspective on shortcomings on the road to clinical translation and production.

Greatly isolated heterogeneous circulating tumor cells using hybrid engineered cell membrane-camouflaged magnetic nanoparticles

BACKGROUND

Circulating tumor cells (CTCs) are considered as a useful biomarker for early cancer diagnosis, which play a crucial role in metastatic process. Unfortunately, the tumor heterogeneity and extremely rare occurrence rate of CTCs among billions of interfering leukocytes seriously hamper the sensitivity and purity of CTCs isolation.

METHODS

To address these, we firstly used microfluidic chips to detect the broad-spectrum of triple target combination biomarkers in CTCs of 10 types of cancer patients, including EpCAM, EGFR and Her2. Then, we constructed hybrid engineered cell membrane-camouflaged magnetic nanoparticles (HE-CM-MNs) for efficient capture of heterogeneous CTCs with high-purity, which was enabled by inheriting the recognition ability of HE-CM for various CTCs and reducing homologous cell interaction with leukocytes. Compared with single E-CM-MNs, HE-CM-MNs showed a significant improvement in the capture efficiency for a cell mixture, with an efficiency of 90%. And the capture efficiency of HE-CM-MNs toward 12 subpopulations of tumor cells was ranged from 70 to 85%. Furthermore, by using HE-CM-MNs, we successfully isolated heterogeneous CTCs with high purity from clinical blood samples. Finally, the captured CTCs by HE-CM-MNs could be used for gene mutation analysis.

CONCLUSIONS

This study demonstrated the promising potential of HE-CM-MNs for heterogeneous CTCs detection and downstream analysis.

Generally applicable circulating tumor cell enrichment and identification through a membrane glycoprotein-targeting strategy combining magnetic isolation and biological orthogonality labeling

Although the importance of circulating tumor cells (CTCs) has been widely recognized, it is still a challenge to realize high-efficiency and accurate enrichment and identification of highly heterogeneous CTCs derived from various types of tumors in complex cancer processes. Currently, the most widely used methods follow the general idea of sequential immunoaffinitive capture and immunostaining to achieve the abovementioned goal. However, different organ/tissue origins as well as the inherent heterogeneity of CTCs would lead to the missed detection of certain CTC subtypes using such methods. Further, immunocytochemistry (ICC) immunostaining disrupts the physiological structure of cells, severely limiting the detection and application scenarios that require the participation of live cells. To address these limitations, we have developed a generally applicable strategy for the isolation and labeling of CTCs. This strategy focuses on targeting the universal characteristics of all tumor cells, specifically the abnormally expressed cell membrane glycoproteins, such as the transferrin receptor and sialic acid. Strategically, transferrin-functionalized magnetic beads (TMBs) were applied to enrich CTCs, and azide-based bioorthogonal chemistry was employed to label target CTCs. Accordingly, the membrane glycoprotein-targeting strategy achieved unbiased enrichment and labeling of broad-spectrum CTCs that were both epithelial and non-epithelial phenotypic populations with varied organ/tissue origins (MCF-7, HepG2, A549, Jurkat, and B16), with a capture efficiency of >95% and a detection limit as low as 5 cells per mL in artificial blood. In particular, our developed strategy displayed excellent specificity, and the CTCs under capture and fluorescence labelling remained with good viability and could be further cultivated and analyzed. Finally, the membrane glycoprotein-targeting strategy successfully detected and identified 33-223 CTCs from 1 mL patient blood samples.

Antifouling modification for high-performance isolation of circulating tumor cells

Circulating tumor cells (CTCs), which shed from solid tumor tissue into blood circulatory system, have attracted wide attention as a biomarker in the early diagnosis and prognosis of cancer. Given their potential significance in clinics, many platforms have been developed to separate CTCs. However, the high-performance isolation of CTCs remains significant challenges including achieving the sensitivity and specificity necessary due to their extreme rarity and severe biofouling in blood, such as billions of background cells and various proteins. With the advancement of CTCs detection technologies in recent years, the highly efficient and highly specific detection platforms for CTCs have gradually been developed, resulting in improving CTC capture efficiency, purity and sensitivity. In this review, we systematically describe the current strategies with surface modifications by utilizing the antifouling property of polymer, peptide, protein and cell membrane for high-performance enrichment of CTCs. To wrap up, we discuss the substantial challenges facing by current technologies and the potential directions for future research and development.

Advanced targeted drug delivery by bioengineered white blood cell-membrane camouflaged nanoparticulate delivery nanostructures

Targeted drug delivery has emerged as a pivotal approach within precision medicine, aiming to optimize therapeutic efficacy while minimizing systemic side effects. Leukocyte membrane coated nanoparticles (NPs) have attracted a lot of interest as an effective approach for delivering targeted drugs, capitalizing on the natural attributes of leukocytes to achieve site-specific accumulation, and heightened therapeutic outcomes. An overview of the present state of the targeted medication delivery research is given in this review. Notably, Leukocyte membrane-coated NPs offer inherent advantages such as immune evasion, extended circulation half-life, and precise homing to inflamed or diseased tissues through specific interactions with adhesion molecules. leukocyte membrane-coated NPs hold significant promise in advancing targeted drug delivery for precision medicine. As research progresses, they are anticipated to contribute to improved therapeutic outcomes, enabling personalized and effective treatments for a wide range of diseases and conditions. The review covers the method of preparation, characterization, and biological applications of leucocytic membrane coated NPs. Further, patents related factors, gap of translation from laboratory to clinic, and future prospective were discussed in detail. Overall, the review covers extensive literature to establish leucocytic membrane NPs for targeted drug delivery.

Biomimetic Systems Involving Macrophages and Their Potential for Targeted Drug Delivery

The concept of targeted drug delivery can be described in terms of the drug systems' ability to mimic the biological objects' property to localize to target cells or tissues. For example, drug delivery systems based on red blood cells or mimicking some of their useful features, such as long circulation in stealth mode, have been known for decades. On the contrary, therapeutic strategies based on macrophages have gained very limited attention until recently. Here, we review two biomimetic strategies associated with macrophages that can be used to develop new therapeutic modalities: first, the mimicry of certain types of macrophages (i.e., the use of macrophages, including tumor-associated or macrophage-derived particles as a carrier for the targeted delivery of therapeutic agents); second, the mimicry of ligands, naturally absorbed by macrophages (i.e., the use of therapeutic agents specifically targeted at macrophages). We discuss the potential applications of biomimetic systems involving macrophages for new advancements in the treatment of infections, inflammatory diseases, and cancer.

Cell membrane-based nanomaterials for theranostics of central nervous system diseases

Central nervous system (CNS) diseases have been widely acknowledged as one of the major healthy concerns globally, which lead to serious impacts on human health. There will be about 135 million CNS diseases cases worldwide by mid-century, and CNS diseases will become the second leading cause of death after the cardiovascular disease by 2040. Most CNS diseases lack of effective diagnostic and therapeutic strategies with one of the reasons that the biological barrier extremely hampers the delivery of theranostic agents. In recent years, nanotechnology-based drug delivery is a quite promising way for CNS diseases due to excellent properties. Among them, cell membrane-based nanomaterials with natural bio-surface, high biocompatibility and biosafety, are of great significance in both the diagnosis and treatment of different CNS diseases. In this review, the state of art of the fabrication of cell membranes-based nanomaterials is introduced. The characteristics of different CNS diseases, and the application of cell membranes-based nanomaterials in the theranostics are summarized. In addition, the future prospects and limitations of cell membrane nanotechnology are anticipated. Through summarizing the state of art of the fabrication, giving examples of CNS diseases, and highlighting the applications in theranostics, the current review provides designing methods and ideas for subsequent cell membrane nanomaterials.

Dual Stealth Functional Immuno-magnetic Nanoparticles for High-Performance Isolation of Circulating Tumor Cells

As a biomarker of hepatocellular carcinoma (HCC) biopsy, circulating tumor cells (CTCs) are often used in the diagnosis of cancer and treatment guidance. For CTCs detection, immuno-magnetic nanoparticles (IMNs) are one of the most commonly used platforms. However, the nonspecific adsorption of proteins and non-tumor cells weakens the performance of IMNs to capture CTCs. In this work, we developed an IMNs platform which was constructed by a biomimetic protein corona precoating and a polyethylene glycol (PEG) spacer to form the PEG and corona-coated IMNs (IP-CMNs). Due to the dual stealth effect of protein corona precoating and PEG spacer, the nonspecific protein adsorption and cell binding of P-CMNs could reduce by ∼5.5- and ∼5.4-fold, respectively, compared with those of unmodified particles. Furthermore, the PEG spacer could not only reduce the interaction between IP-CMNs and leukocytes but also enhance the capture performance toward tumor cells. By using artificial blood samples, the capture efficiency of IP-CMNs toward rare CTCs was found to be 88.3%, while it was 70.5% by using commercial IMNs. Finally, CTCs were successfully isolated in all HCC patient blood samples (7/7) using IP-CMNs. These results provide insight into the use of the multifunctional nanoplatform as a useful tool for CTCs detection.

Boosting the integration of cell membrane-nanomaterial hybrids via dextran-mediated dynamic dispersion system to capture bioactive compounds in natural products

Efficient integration is a prerequisite for the application of cell membrane-nanomaterial hybrids (CN hybrids) in bioanalysis, however, the poor dispersity of nanomaterials limits the development of this technology. Although the traditional hydrophilic modification method could improve the dispersity of nanomaterials, it would hinder the coating of the cell membrane, thus making it unsuitable for the integration of CN hybrids. Herein, a method has been proposed to improve the integration efficiency of CN hybrids from a different perspective, that is, establishing a dynamic dispersion system to enhance the interfacial interaction between cell membranes and nanomaterials. Specifically, magnetic graphene oxide (MGO) nanosheets were used as the model carrier and HepG2 cells were used as the source for membrane coating. The addition of the macromolecular stabilizer dextran to the integration process enhanced the dispersity of MGO and avoided the resistance to membrane coating caused by surface modification. Intriguingly, MGO in the dynamic dispersion system showed superior membrane coating ability as compared to hydrophilic modification methods, resulting in the more efficient integration of CN hybrids and greater sensitivity in capturing bioactive compounds from natural products. The proposed design principle provides a brand-new perspective for optimizing the behavior of CN hybrids and can improve the effectiveness of CN hybrids in bioanalytical applications.

A multifunctional black phosphorus nanosheet-based immunomagnetic bio-interface for heterogeneous circulating tumor cell capture and simultaneous self-identification in gastric cancer patients

A single epithelial cell adhesion molecule (EpCAM) for circulating tumor cell (CTCs) isolation has been proved to be low in efficiency as it fails to recognize EpCAM-negative CTCs. Meanwhile, the current immunocytochemical (ICC) identification strategy for the captured cells is tedious and time-consuming. To address these issues, we designed a dual-labeled fluorescent immunomagnetic nanoprobe (BP-Fe₃O₄-AuNR/Apt), by loading magnetic Fe₃O₄ nanoparticles and gold nanorods (AuNRs) onto black phosphorus (BP) nanosheets and then linking them with Cy3-labeled EpCAM and Texas red-labeled tyrosine protein kinase 7 (PTK7) aptamers, which created a high-performance bio-interface for efficient, heterogeneous CTC capture and rapid self-identification with high accuracy. As few as 5 CTCs could be captured from 1.0 mL PBS, mixed cell solution and lysed blood. What's more, the presence of BP and AuNRs on this capturing interface also allowed us to preliminarily investigate the potential photothermal therapeutic effect of the probe toward CTC elimination. The applicability of the probe was further demonstrated in gastric cancer patients. By detecting the number of CTCs in the blood of gastric cancer patients, the correlations between the CTC number and the disease stage, as well as distant metastasis were systematically explored.

Cell Membrane and V2C MXene-Based Electrochemical Immunosensor with Enhanced Antifouling Capability for Detection of CD44

The inactive adsorption and interference of biomolecules in electrochemical biosensors is a topic of intense interest. Directly utilizing native cell membranes to endow electrochemical surfaces with antifouling and biocompatible features is a promising strategy, rather than attempting to synthetically replicate complex biological interface properties. In this study, we present a facial and sensitive sandwich-type antifouling immunoassay through platelet membrane/Au nanoparticle/delaminated V₂C nanosheet (PM/AuNPs/d-V₂C)-modified electrode as the substrate of sensing interface and methylene blue/aminated metal organic framework (MB@NH₂-Fe-MOF-Zn) as an electrochemical signal probe. The biosensor perfectly integrates the high conductivity of AuNPs-loaded V₂C MXene with the excellent loading property of NH₂-Fe-MOF-Zn to improve the electrochemical sensing performance. In addition, the excellent antifouling properties of the homogeneous cell membrane can effectively prevent the non-specific adsorption of model proteins. The obtained antifouling biosensor possesses the capability of ultrasensitive detection of CD44 and CD44-positive cancer cell in complex liquids and exhibits good analytical performance for the analysis of CD44 with a linear range from 0.5 ng/mL to 500 ng/mL. This strategy of developing cell membrane-based biosensing systems with enhanced antifouling capability can be easily expanded to the construction of other complex biosensors, and the advanced biological probes and analytical methods provide a favorable means to accurately quantify biomarkers associated with tumor progression.

Nano-omics: nanotechnology-based multidimensional harvesting of the blood-circulating cancerome

Over the past decade, the development of 'simple' blood tests that enable cancer screening, diagnosis or monitoring and facilitate the design of personalized therapies without the need for invasive tumour biopsy sampling has been a core ambition in cancer research. Data emerging from ongoing biomarker development efforts indicate that multiple markers, used individually or as part of a multimodal panel, are required to enhance the sensitivity and specificity of assays for early stage cancer detection. The discovery of cancer-associated molecular alterations that are reflected in blood at multiple dimensions (genome, epigenome, transcriptome, proteome and metabolome) and integration of the resultant multi-omics data have the potential to uncover novel biomarkers as well as to further elucidate the underlying molecular pathways. Herein, we review key advances in multi-omics liquid biopsy approaches and introduce the 'nano-omics' paradigm: the development and utilization of nanotechnology tools for the enrichment and subsequent omics analysis of the blood-circulating cancerome.

Protein corona-coated immunomagnetic nanoparticles with enhanced isolation of circulating tumor cells

Immunomagnetic nanoparticles (IMNs) have been widely developed as a detection tool to isolate rare circulating tumor cells (CTCs) from whole blood as a potential method for early cancer diagnosis, metastasis examination, and treatment guidance. However, a spontaneous interaction between nanoparticles and proteins results in the formation of a protein corona that reduces the performance of IMNs when they enter body fluids. To address this issue, the protein corona was precoated onto magnetic nanoparticles (C-MNs), and then their surfaces were conjugated with an immuno-antibody. The adsorption of proteins on C-MNs was decreased 6-fold and non-specific cell binding was reduced 5-fold, compared with magnetic nanoparticles (MNs). Furthermore, the immuno-antibody functionalized C-MNs (IC-MNs) maintained highly specific CTC capture performance when exposed to blood plasma. By using artificial spiked blood samples, IC-MNs exhibited 90.2% CTC isolation efficiency, compared with 60.3% by using IMNs. IC-MNs also successfully captured CTCs with high purity in 24 out of 26 female breast cancer patient blood samples. This work demonstrated that a novel preformed protein corona strategy can provide a useful clinically applicable diagnostic tool.

Noninvasive Optical Isolation and Identification of Circulating Tumor Cells Engineered by Fluorescent Microspheres

Circulating tumor cells (CTCs) are rare, meaning that current isolation strategies can hardly satisfy efficiency and cell biocompatibility requirements, which hinders clinical applications. In addition, the selected cells require immunofluorescence identification, which is a time-consuming and expensive process. Here, we developed a method to simultaneously separate and identify CTCs by the integration of optical force and fluorescent microspheres. Our method achieved high-purity separation of CTCs without damage through light manipulation and avoided additional immunofluorescence staining procedures, thus achieving rapid identification of sorted cells. White blood cells (WBCs) and CTCs are similar in size and density, which creates difficulties in distinguishing them optically. Therefore, fluorescent PS microspheres with high refractive index (RI) are designed here to capture the CTCs (PS-CTCs) and increase the average index of refraction of PS-CTCs. In optofluidic chips, PS-CTCs were propelled to the collection channel from the sample mixture, under the radiation of light force. Cells from the collection outlet were easily identified under a fluorescence microscope due to the fluorescence signals of PS microspheres. This method provides an approach for the sorting and identification of CTCs, which holds great potential for clinical applications in early diagnosis of disease.

White Blood Cell Membrane-Coated Nanoparticles: Recent Development and Medical Applications

White blood cells (WBCs) are immune cells that play essential roles in critical diseases including cancers, infections, and inflammatory disorders. Their dynamic and diverse functions have inspired the development of WBC membrane-coated nanoparticles (denoted "WBC-NPs"), which are formed by fusing the plasma membranes of WBCs, such as macrophages, neutrophils, T cells, and natural killer cells, onto synthetic nanoparticle cores. Inheriting the entire source cell antigens, WBC-NPs act as source cell decoys and simulate their broad biointerfacing properties with intriguing therapeutic potentials. Herein, the recent development and medical applications of WBC-NPs focusing on four areas, including WBC-NPs as carriers for drug delivery, as countermeasures for biological neutralization, as nanovaccines for immune modulation, and as tools for the isolation of circulating tumor cells and fundamental research is reviewed. Overall, the recent development and studies of WBC-NPs have established the platform as versatile nanotherapeutics and tools with broad medical application potentials.

Controllable Environment Protein Corona-Disguised Immunomagnetic Beads for High-Performance Circulating Tumor Cell Enrichment

The enrichment performance of immunomagnetic beads (IMBs) in blood samples is usually challenging due to the ungoverned, in situ-formed protein corona, as it generally leads to negative effects, such as impeded targeting capacity and unwanted nonspecific absorption. On the contrary, a controlled protein premodification of IMBs with diverse functional environment (blood) proteins endows the composites with a new biological identity and may improve the anti-nonspecific ability, resulting in promising isolation benefits for circulating tumor cell (CTC) enrichment and downstream analyses. Specifically, fetal bovine serum and the four most abundant blood proteins, including human serum albumin, fibrinogen, immunoglobulin, and transferrin, were separately applied in this work. Conclusively, the biological properties of the applied protein corona camouflage have a great influence on the capture performance of IMBs, and certain proteins can enhance the enrichment performance to a large extent. Promisingly, human serum albumin-camouflaged IMBs (HSA-PIMBs) achieved a capture efficiency of 84.0-90.0% and significantly minimized nonspecific absorbed leukocytes to 164-264 in blood samples (0.5 mL, 25-55 model CTCs). Furthermore, HSA-PIMBs isolated 62-505 CTCs and 13-31 leukocytes from the blood samples of five cancer patients. The novel environment camouflage strategy provides a new insight into protein corona utilization and may improve the performance of targeted nanomaterials in a complex biological environment.

A light-induced hydrogel responsive platform to capture and selectively isolate single circulating tumor cells

Isolation of circulating tumor cells (CTCs) from patients is a challenge due to the rarity of CTCs. Recently, various platforms to capture and release CTCs for downstream analysis have been developed. However, most of the reported release methods provide external stimuli to release all captured cells, which lead to lack of specificity in the pool of collected cells, and the external stimuli may affect the activity of the released cells. Here, we presented a simple method for single-cell recovery to overcome the shortcomings, which combined the nanostructures with a photocurable hydrogel, chondroitin sulfate methacryloyl (CSMA). In brief, we synthesized gelatin nanoparticles (Gnps) and modified them on flat glass (Gnp substrate) for the specific capture of CTCs. A 405 nm laser was projected onto the selected cells, and then CSMA was cured to encapsulate the selected CTCs. Unselected cells were removed with MMP-9 enzyme solution, and selected CTCs were recovered using a microcapillary. Finally, the photocurable hydrogel-encapsulated cells were analyzed by nucleic acid detection. In addition, the results suggested that the isolation platform showed good biocompatibility and successfully achieved the isolation of selected cells. In summary, our light-induced hydrogel responsive platform holds certain potential for clinical applications.

Artificial cell membrane camouflaged immunomagnetic nanoparticles for enhanced circulating tumor cells isolation

Precise and specific circulating tumor cells (CTCs) isolation is heavily interfered by blood cells and proteins. Though satisfactory results have been achieved by some cell membrane-derived platforms, following limitations have...

Cell membrane-engineered nanoparticles for cancer therapy

Cell-membrane-coated nanotechnology involves dressing the synthetic nanoparticles (NPs) with membrane derived from different types of cells to endow the NPs with the properties of a specific cell type and to further...

Immuno-affinitive supramolecular magnetic nanoparticles incorporating cucurbit[8]uril-mediated ternary host-guest complexation structures for high-efficient small extracellular vesicle enrichment

Enriching small extracellular vesicles (sEVs) with undamaged structure and function is a pivotal step for further applications in biological and clinical fields. It has prompted researchers to explore a carrier material that can efficiently capture sEVs while also gently release the captured sEVs. Here, 1-adamantylamine (1-ADA) responsive immuno-affinitive supramolecular magnetic nanoparticles (ISM-NPs) incorporating ternary host-guest complexation structures mediated by CB[8] were proposed to achieved the goal. In particular, the ternary host-guest complexation was constructed by the host molecule (cucurbit[8]uril, CB[8]) mediated assembly of two guest molecules (naphthol and bipyridine), and served as a cleavable bridge to connect the magnetic core and peripheral antibody. These constructed ISM-NPs performed well in the applications of capturing sEVs with a high capture efficiency of 85.5%. Further, the CB[8]-mediated ternary host-guest complexation structures can be disassembled with addition of the 1-ADA. Thus, the sEVs recognized by the anti-CD63 were released competitively, with a decent release efficiency more than 82%. The released sEVs kept intact morphology and exhibited appropriate size distribution and concentration. This supramolecular magnetic system, with 1-ADA responsive ternary host-guest complexation structures, may contribute to efficient enrichment of any other biomarkers, likely cells, proteins, peptides, etc.

Cell Membrane-Coated Mimics: A Methodological Approach for Fabrication, Characterization for Therapeutic Applications, and Challenges for Clinical Translation

Cell membrane-coated (CMC) mimics are micro/nanosystems that combine an isolated cell membrane and a template of choice to mimic the functions of a cell. The design exploits its physicochemical and biological properties for therapeutic applications. The mimics demonstrate excellent biological compatibility, enhanced biointerfacing capabilities, physical, chemical, and biological tunability, ability to retain cellular properties, immune escape, prolonged circulation time, and protect the encapsulated drug from degradation and active targeting. These properties and the ease of adapting them for personalized clinical medicine have generated a significant research interest over the past decade. This review presents a detailed overview of the recent advances in the development of cell membrane-coated (CMC) mimics. The primary focus is to collate and discuss components, fabrication methodologies, and the significance of physiochemical and biological characterization techniques for validating a CMC mimic. We present a critical analysis of the two main components of CMC mimics: the template and the cell membrane and mapped their use in therapeutic scenarios. In addition, we have emphasized on the challenges associated with CMC mimics in their clinical translation. Overall, this review is an up to date toolbox that researchers can benefit from while designing and characterizing CMC mimics.

Emerging strategies in developing multifunctional nanomaterials for cancer nanotheranostics

Cancer involves a collection of diseases with a common trait - dysregulation in cell proliferation. At present, traditional therapeutic strategies against cancer have limitations in tackling various tumors in clinical settings. These include chemotherapeutic resistance and the inability to overcome intrinsic physiological barriers to drug delivery. Nanomaterials have presented promising strategies for tumor treatment in recent years. Nanotheranostics combine therapeutic and bioimaging functionalities at the single nanoparticle level and have experienced tremendous growth over the past few years. This review highlights recent developments of advanced nanomaterials and nanotheranostics in three main directions: stimulus-responsive nanomaterials, nanocarriers targeting the tumor microenvironment, and emerging nanomaterials that integrate with phototherapies and immunotherapies. We also discuss the cytotoxicity and outlook of next-generation nanomaterials towards clinical implementation.

Engineered multifunctional metal-phenolic nanocoatings for label-free capture and "self-release" of heterogeneous circulating tumor cells

Immunomagnetic beads have been widely explored as an important analytical tool for the rapid and sensitive detection of circulating tumor cells (CTCs). However, their clinical application is seriously hindered by the tedious preparation procedures and heterogeneous nature of CTCs. To this end, a designed multifunctional platform named Fe₃O₄@TA/Cu^II superparamagnetic nanoparticles (SPMNPs) is expected to have the following features: (i) the formation of a tannic acid-copper (II) ion (TA/Cu^II) coating which could be accomplished by a one-step method is very simple; (ii) the TA/Cu^II coating shows high affinity for heterogeneous CTCs and good resistance to nonspecific adhesion of blood cells; (iii) "self-release" of the captured cells could be achieved as the TA/Cu^II coating gradually degrades in the cell culture environment without any additional interventions. Therefore, the resulting Fe₃O₄@TA/Cu^II SPMNPs could capture various CTCs (MCF-7, HepG2 and HeLa cells) with different expression levels of the epithelial cell adhesion molecule (EpCAM). And the capture efficiency and cell purity can reach 88% and 87%, respectively. In addition, 68% of the captured cells are self-released after 6 h of incubation and most of the released cells show high cell proliferation activity. In particular, Fe₃O₄@TA/Cu^II SPMNPs can successfully detect 1-13 CTCs from 1 mL of blood of 14 patients with 6 types of cancers. Hence, we expect that the as-prepared Fe₃O₄@TA/Cu^II SPMNPs with simple, efficient, and universal yet cost-efficient characteristics could act as a promising analytical tool for clinical CTC detection.

Reversible capturing and voltammetric determination of circulating tumor cells using two-dimensional nanozyme based on PdMo decorated with gold nanoparticles and aptamer

A novel cytosensor was constructed for the ultrasensitive detection and nondestructive release of circulating tumor cells (CTCs) by combining Au nanoparticles-loaded two-dimensional bimetallic PdMo (2D Au@PdMo) nanozymes and electrochemical reductive desorption. The 2D Au@PdMo nanozymes possessed high-efficiency peroxidase-like activity and were assembled with an aptamer composed of a thiol-modified epithelial specific cell adhesion molecule (EpCAM) to strengthen CTCs adhesion. Moreover, the electrode surface was decorated with highly fractal Au nanostructures (HFAuNSs) composites due to the similarity in fractal nanostructure with the CTCs membrane to enhance the CTCs anchoring efficiency and release capability. The captured CTCs could be further efficiently dissociated and nondestructively released from the modified electrodes upon electrochemical reductive desorption. The designed cytosensor showed an excellent analytical performance, with a wide linear range from 2 to 1 × 10⁵ cells mL^-1 and low limit of detection (LOD) of 2 cells mL^-1 (S/N = 3) at the working potential in the range  -0.6 to 0.2 V. A satisfactory CTCs release reaching a range of 93.7-97.4% with acceptable RSD from 3.55 to 6.41% and good cell viability was obtained. Thus, the developed cytosensor might provide a potential alternative to perform CTC-based liquid biopsies, with promising applications in early diagnosis of tumors. Preparation and mechanism of desorption of the cytosensor based on 2D Au@PdMo nanozymes and electrochemical reductive desorption for the detection and release of CTCs. A Preparation procedure of the Apt/Au@PbMo bioconjugates. B Fabrication process of the sandwich-type cytosensor. C Electrochemical signal produced by the Au@PdMo nanozymes. D Mechanism of electrochemical reductive desorption for CTCs release.

Dynamic nanoassembly-based drug delivery system (DNDDS): Learning from nature

Dynamic nanoassembly-based drug delivery system (DNDDS) has evolved from being a mere curiosity to emerging as a promising strategy for high-performance diagnosis and/or therapy of various diseases. However, dynamic nano-bio interaction between DNDDS and biological systems remains poorly understood, which can be critical for precise spatiotemporal and functional control of DNDDS in vivo. To deepen the understanding for fine control over DNDDS, we aim to explore natural systems as the root of inspiration for researchers from various fields. This review highlights ingenious designs, nano-bio interactions, and controllable functionalities of state-of-the-art DNDDS under endogenous or exogenous stimuli, by learning from nature at the molecular, subcellular, and cellular levels. Furthermore, the assembly strategies and response mechanisms of tailor-made DNDDS based on the characteristics of various diseased microenvironments are intensively discussed. Finally, the current challenges and future perspectives of DNDDS are briefly commented.

Hybrid Membrane-Coated Biomimetic Nanoparticles (HM@BNPs): A Multifunctional Nanomaterial for Biomedical Applications

The application of nanoparticles in the diagnosis and treatment of diseases has undergone different developmental stages, but phagocytosis and nonspecific distribution have been the main factors restricting the transformation of nanobased drugs into clinical practice. In the past decade, the design of membrane-coated nanoparticles has gained increasing attention. It is hoped that the combination of the cell membrane's natural biological properties and the functional integration of synthetic nanoparticle systems can compensate for the shortage of traditional nanoparticles. The membrane coating gives the nanoparticles unique biological functions such as immune evasion and targeting capability. However, when the encapsulation of monotypic membranes does not meet the diverse demands of biomedicine, the combination of different cell membranes may offer more possibilities. In this review, the composition, preparation, and advantages of biomimetic nanoparticles coated with hybrid cell membranes are summarized, and the applications of hybrid membrane-coated biomimetic nanoparticles (HM@BNPs) in drug delivery, phototherapy, liquid biopsy, tumor vaccines, immune therapy, and detoxification are reviewed. Finally, the current challenges and opportunities with regard to HM@BNPs are discussed.

Biomineralized synthesis of a smart O2-regenerating nanoreactor for highly efficient starvation/gas therapy

The emerging starvation therapy holds great promise in cancer treatment, however, its therapeutic effect is heavily reduced by intracellular hypoxia and high glutathione (GSH) conditions. To overcome these limitations, a new concept of starvation therapy pattern that employs biodegradable carriers with special selectivity and exhibits excellent anti-migration and therapy effect without using any invasive chemotherapy drugs was developed. A facile biomineralization method is first chosen to synthesize human serum albumin and folic acid modified MnO2 to guarantee active targeting, long-term stability and responsive degradation in tumor microenvironment. Designed degradation remarkably reduces GSH contents and hugely elevates intracellular O2 levels, both of which significantly improve the catalytic efficiency of GOX. Furthermore, the by-product of H2O2 is intelligently used to oxidize L-arginine and the generated NO results into effective gas therapy. More importantly, the first anti-migration case of starvation therapy has been reported in this work, and detailed molecular mechanism study uncovers that lysosome damage and changes of mitochondria membrane potential contribute to cell apoptosis. This work opens up new ideas to construct novel green yet noninvasive methods to treat cancer and inhibit migration by using degradable carriers and endogenous substances to minimize adverse effect.

High-Specific Isolation and Instant Observation of Circulating Tumour Cell from HCC Patients via Glypican-3 Immunomagnetic Fluorescent Nanodevice

PURPOSE

Specific targeting receptors for efficiently capturing and applicable nanodevice for separating and instant observing of circulating tumour cells (CTC) are critical for early diagnosis of cancer. However, the existing CTC detection system based on epithelial cell adhesion molecule (EpCAM) was seriously limited by low expression and poor specificity of targeting receptors, and not instant observation in clinical application.

METHODS

Herein, an alternative glypican-3 (GPC3)-based immunomagnetic fluorescent system (C6/MMSN-GPC3) for high-specific isolation and instant observation of CTC from hepatocellular carcinoma (HCC) patients' peripheral blood was developed. The high-specific HCC targeting receptor, GPC3, was employed for improving the sensitivity and accuracy in CTC detection. GPC3 monoclonal antibody (mAb) was linked to immunomagnetic mesoporous silica for specific targeting capture and separate CTC, and fluorescent molecule coumarin-6 (C6) was loaded for instant detection of CTC.

RESULTS

The cell recovery (%) of C6/MMSN-GPC3 increased in 106 HL-60 cells (from 49.7% to 83.0%) and in whole blood (from 42% to 80.3%) compared with MACS® Beads. In clinical samples, the C6/MMSN-GPC3 could capture more CTC in the 13 cases of HCC patients and the capture efficiency was improved by 83.3%-350%. Meanwhile, the capture process of C6/MMSN-GPC3 was harmless, facilitating for the subsequent culture. Significantly, the C6/MMSN-GPC3 achieved the high-specific isolation and instant observation of CTC from HCC patients' blood samples, and successfully separated CTC from one patient with early stage of HCC (Stage I) and one post-surgery patient, further indicating the potential ability of C6/MMSN-GPC3 for HCC early diagnosis and prognosis evaluation.

CONCLUSION

Our study provides a feasible glypican-3 (GPC3)-based immunomagnetic fluorescent system (C6/MMSN-GPC3) for high-specific isolation and instant observation of HCC CTC.

Ultradense Erythrocyte Bionic Layer Used to Capture Circulating Tumor Cells and Plasma-Assisted High-Purity Release

The isolation and detection of rare circulating tumor cells (CTCs) from patient peripheral blood can help early diagnosis of cancer and evaluation of therapeutic outcomes. At present, most of the available strategies for enriching CTCs face serious problems with purity due to the nonspecific interactions between the capture medium and leukocytes. Inspired by the immune evasion ability of homologous red blood cells (RBCs), we modified the tumor-targeting molecule folic acid (FA) on the surface of RBCs by hydrophobic interactions. Under the treatment of polybrene, the charges on the surface of RBCs are neutralized, which reduces the mutual repulsion force. Furthermore, RBCs treated with polyethylene also have excellent deformability, thereby enabling engineered RBCs to form a dense bionic layer on the adhesive glass slide, which can greatly inhibit the nonspecific adhesion of leukocytes. The bionic layer can achieve high-purity enrichment of tumor cells in phosphate-buffered saline (PBS), and we can achieve high-activity release in plasma. The cell count showed over 80% capture efficiency and over 70% release rate, and the purity of CTCs obtained in the artificial blood sample after release was higher than 90%. The RBC bionic surface coating is notably cost-effective and highly applicable for CTC isolation in clinic practice, and thus provides new prospects for designing cell-material interfaces for advanced cell-based biomedical studies in the future.

Cell-Released Magnetic Vesicles Capturing Metabolic Labeled Rare Circulating Tumor Cells Based on Bioorthogonal Chemistry

Capture of circulating tumor cells (CTCs) with high efficiency and high purity holds great value for potential clinical applications. Besides the existing problems of contamination from blood cells and plasma proteins, unknown/down-regulated expression of targeting markers (e.g., antigen, receptor, etc.) of CTCs have questioned the reliability and general applicability of current CTCs capture methodologies based on immune/aptamer-affinity. Herein, a cell-engineered strategy is designed to break down such barriers by employing the cell metabolism as the leading force to solve key problems. Generally, through an extracellular vesicle generation way, the cell-released magnetic vesicles inherited parent cellular membrane characteristics are produced, and then functionalized with dibenzoazacyclooctyne to target and isolate the metabolic labeled rare CTCs. This strategy offers good reliability and broader possibilities to capture different types of tumor cells, as proven by the capture efficiency above 84% and 82% for A549 and HepG2 cell lines as well as an extremely low detection limitation of 5 cells. Moreover, it enabled high purity enrichment of CTCs from 1 mL blood samples of tumor-bearing mice, only ≈5-757 white blood cells are non-specific caught, ignoring the potential phenotypic fluctuation associated with the cancer progression.

Recent Advances in Macrophage-Mediated Drug Delivery Systems

Macrophages have been extensively used in the development of drug delivery systems, as they can prolong the circulation and release of drugs, extend their half-life, increase their stability and targeting ability, and reduce immunogenicity. Moreover, they have good biocompatibility and degradability and offer abundant surface receptors for targeted delivery of a wide variety of drugs. Macrophage-mediated drug delivery systems can be prepared by loading drugs or drug-loaded nanoparticles into macrophages, macrophage membranes or macrophage-derived vesicles. Although such systems can be used to treat inflammation, cancer, HIV infection and other diseases, they require further research and optimization since they have been assembled from diverse sources and therefore can have quite different physical and chemical properties. Moreover, potential cell-drug interactions can limit their application, and the biological activity of membrane proteins might be lost during membrane extraction and storage. In this review, we summarize the recent advances in this field and discuss the preparation of macrophage-mediated drug delivery systems, their advantages over other delivery systems, their potential applications and future lines of research.

Chemically Engineered Immune Cell-Derived Microrobots and Biomimetic Nanoparticles: Emerging Biodiagnostic and Therapeutic Tools

Over the past decades, considerable attention has been dedicated to the exploitation of diverse immune cells as therapeutic and/or diagnostic cell-based microrobots for hard-to-treat disorders. To date, a plethora of therapeutics based on alive immune cells, surface-engineered immune cells, immunocytes' cell membranes, leukocyte-derived extracellular vesicles or exosomes, and artificial immune cells have been investigated and a few have been introduced into the market. These systems take advantage of the unique characteristics and functions of immune cells, including their presence in circulating blood and various tissues, complex crosstalk properties, high affinity to different self and foreign markers, unique potential of their on-demand navigation and activity, production of a variety of chemokines/cytokines, as well as being cytotoxic in particular conditions. Here, the latest progress in the development of engineered therapeutics and diagnostics inspired by immune cells to ameliorate cancer, inflammatory conditions, autoimmune diseases, neurodegenerative disorders, cardiovascular complications, and infectious diseases is reviewed, and finally, the perspective for their clinical application is delineated.

A magnetic surface-enhanced Raman scattering platform for performing successive breast cancer exosome isolation and analysis

The rapid development of exosome research provides new insights into the physiological role of exosomes and their significant correlation with human health. Although the exosomes derived from tumor sources have been proven to be promising biomarkers for cancer detection and disease progression due to their inherited biological contents from the parent cancer cells and unique roles in tumor metastasis and invasion, it is still a challenging task to perform rapid and effective isolation from complex biological samples and conduct high-precision real-time analysis. Herein, we propose a magnetic surface-enhanced Raman scattering (SERS) platform to integrate successive breast cancer exosome isolation and Raman signal enhancement into one system to achieve the goal. In addition, principal component analysis (PCA) was conducted to investigate major patterns of the samples. According to the results, the magnetic SERS platform can be applied to distinguish exosomes derived from MCF-7 and MDA-MB-231 cells with 100% sensitivity and 100% specificity for the 95% confidence interval. More importantly, this platform can fully identify breast cancer patients and healthy people with 91.67% sensitivity and 100% specificity. These studies revealed that our magnetic SERS platform would serve as a great potential system for highly efficient real-time liquid biopsy by using the exosomes as cancerous markers, while exempting from pre-treatment of clinical samples or the extra introduction of elements for SERS signal enhancement.

A light-up fluorescence resonance energy transfer magnetic aptamer-sensor for ultra-sensitive lung cancer exosome detection

In vitro liquid biopsy based on exosomes offers promising opportunities for fast and reliable detection of lung cancers. In this work, we present a fluorescence resonance energy transfer (FRET) magnetic aptamer-sensor for magnetic enrichment of exosomes with aptamers and detection of cancerous-surface proteins based on a light-up FRET strategy. Fluorescent quantum dots (QDs) and aptamers were introduced onto magnetic nanoparticles and the fluorescence emission turned down when the aptamers were paired with their complementary DNA on the surface of Au nanoparticles. Later, competitive binding of exosomes with the aptamers expelled the Au nanoparticles resulting in an exosome concentration-dependent linear increase of QD fluorescence intensity in a broad exosome concentration range (5 × 10²-5 × 10⁹ particles per mL). As found in our work, this system behaved ultra-sensitively and the calculated detection limit of this FRET magnetic aptamer-sensor was as low as 13 particles per mL. Furthermore, taking epithelial cancer-specific antigen (epithelial cell adhesion molecule, EpCAM) screening as a typical example, our built FRET magnetic aptamer-sensor allowed a rapid and efficient distinction of all the epithelial cancer cases (7 lung cancers and 5 other cancers) from health volunteers with 100% accuracy.

Recent Advances in Cell Membrane-Derived Biomimetic Nanotechnology for Cancer Immunotherapy

Immunotherapy will significantly impact the standard of care in cancer treatment. Recent advances in nanotechnology can improve the efficacy of cancer immunotherapy. However, concerns regarding efficiency of cancer nanomedicine, complex tumor microenvironment, patient heterogeneity, and systemic immunotoxicity drive interest in more novel approaches to be developed. For this purpose, biomimetic nanoparticles are developed to make innovative changes in the delivery and biodistribution of immunotherapeutics. Biomimetic nanoparticles have several advantages that can advance the clinical efficacy of cancer immunotherapy. Thus there is a greater push toward the utilization of biomimetic nanotechnology for developing effective cancer immunotherapeutics that demonstrate increased specificity and potency. The recent works and state-of-the-art strategies for anti-tumor immunotherapeutics are highlighted here, and particular emphasis has been given to the applications of cell-derived biomimetic nanotechnology for cancer immunotherapy.

Enhanced Isolation of Fetal Nucleated Red Blood Cells by Enythrocyte-Leukocyte Hybrid Membrane-Coated Magnetic Nanoparticles for Noninvasive Pregnant Diagnostics

Fetal nucleated red blood cells (fNRBCs) in maternal peripheral blood containing the whole genetic information of the fetus may serve for noninvasive pregnant diagnostics (NIPD). However, the fetal cell-based NIPD is seriously limited by the poor purity of the isolated fNRBCs. Recently, the biomimetic cell membrane-camouflaged nanoparticles containing outstanding features have been widely used to detect and isolate rare cells from the peripheral blood samples. In this work, enythrocyte (RBC) and leukocyte (WBC) membranes are fused and coated onto magnet nanoparticles and then modified with anti-CD147 to isolate fNRBCs from the maternal peripheral blood with significant efficiency (∼90%) and purity (∼87%) in simulated spiked blood samples. Further, fNRBCs were isolated and identified from a series of maternal peripheral blood samples coming from pregnant women of 11-13 gestational weeks, and different chromosomal aneuploidies were diagnosed using fNRBCs isolated from maternal blood in early pregnancy. Our strategy may offer additional opportunity to overcome the limitations of current cell-based NIPD platforms.

Biomimetic hybrid membrane-based nanoplatforms: synthesis, properties and biomedical applications

The rapid clearance and capture by the immune system pose a big challenge in targeted drug delivery using nanocarriers. Cell membrane coating endows nanoplatforms with prolonged blood circulation, enhanced immune escape, and improved targeting capability. However, monotypic cell membrane fails to meet the omnifarious needs of biomedical applications. The combination of different types of cell membranes provides a promising solution to provide multifunctional biomimetic nanoplatforms. In this review, we first discuss the feasibility of constructing biomimetic hybrid membranes and summarize current methods of preparing biomimetic hybrid membrane-based nanoplatforms (BHMNs) and their biomedical applications including drug delivery, cancer detection, detoxification, and cancer vaccines. Finally, the prospects and challenges of utilizing BHMNs for personalized medicine are also discussed.

OPENchip: an on-chip in situ molecular profiling platform for gene expression analysis and oncogenic mutation detection in single circulating tumour cells

Liquid biopsy holds promise towards practical implementation of personalized theranostics of cancer. In particular, circulating tumour cells (CTCs) can provide clinically actionable information that can be directly linked to prognosis or therapy decisions. In this study, gene expression patterns and genetic mutations in single CTCs are simultaneously analysed by strategically combining microfluidic technology and in situ molecular profiling technique. Towards this, the development and demonstration of the OPENchip (On-chip Post-processing ENabling chip) platform for single CTC analysis by epithelial CTC enrichment and subsequent in situ molecular profiling is reported. For in situ molecular profiling, padlock probes that identify specific desired targets to examine biomarkers of clinical relevance in cancer diagnostics were designed and used to create libraries of rolling circle amplification products. We characterize the OPENchip in terms of its capture efficiency and capture purity, and validate the probe design using different cell lines. By integrating the obtained results, molecular analyses of CTCs from metastatic breast cancer (HER2 (ERBB2) gene expression and PIK3CA mutations) and metastatic pancreatic cancer (KRAS gene mutations) patients were demonstrated without any off-chip processes. The results substantiate the potential implementation of early molecular detection of cancer through sequencing-free liquid biopsy.

Cell-Membrane-Based Biomimetic Systems with Bioorthogonal Functionalities

During the past decade, there was a fast development of cell-based biomimetic systems, which are commonly derived from cell membranes, cell vesicles, or living cells. Such systems have unique and inherent bioinspired features originating from their parent biological systems. In particular, they are capable of (i) prolonging blood circulation time, (ii) avoiding immune response, (iii) targeting desired sites, (iv) providing antigens in cancer immunotherapy, and (v) loading and delivering therapeutic or imaging agents. Thus, these biomimetic systems are promising as prevention, detection, diagnosis, and therapeutic modalities. Though promising, these cell-based biomimetic systems are still far from wide application. One of the important reasons is the inevitable difficulty in their further efficient and precise functionalization. Bioorthogonal chemistry results in fast, specific, and high-yielding ligation under mild biological conditions without interactions with surrounding biomolecules or disturbance of the whole biosystem. Moreover, bioorthogonal chemical groups can be introduced into cells, especially into cell membranes, through cellular biosynthesis and metabolic incorporation. Hence, a specific and reliable approach for cell membrane functionalization based on bioorthogonal chemistry has been opportunely put forward and rapidly developed. In this Account, we summarize our recent research on the development of biomimetic systems by integrating bioorthogonal chemistry with biomimetic approaches. First, an exogenously supplied unnatural biosynthetic precursor (e.g., an amino acid or lipid) bearing a bioorthogonal group (e.g., azide or tetrazine) is fed to living cells and metabolically incorporated into targeted biomolecules via cellular biosynthesis regardless of the cell phenotype. After that, different functional molecules can be anchored to the cell membranes through bioorthogonal chemical reactions by using previously inserted "artificial chemical groups". Therefore, this safe, direct, and long-term engineering strategy endows the natural cell-based biomimetic systems with additional chemical or biological performances such as labeling, targeting, imaging, and therapeutic capabilities, providing a powerful tool for the construction of biomimetic systems. Interestingly, we have successfully fabricated various biomimetic systems and applied them in (1) living virus labeling, (2) targeting delivery and enrichment of drugs/imaging agents, and (3) disease theranostics. This Account may contribute to the further development of biomimetic systems and facilitate their biological and biomedical applications in the future. With this Account we also hope to attract more cooperative interests from different fields such as chemistry, materials science, biology, pharmacy, and medicine in promoting lab-to-clinic translation of cell-based biomimetic systems combined with these two cutting-edge techniques.

Engineering biomimetic graphene nanodecoys camouflaged with the EGFR/HEK293 cell membrane for targeted capture of drug leads

A novel cell membrane camouflaged graphene-based nanodecoy with targeting properties was first established for drug lead screening.

High-Efficiency Isolation and Rapid Identification of Heterogeneous Circulating Tumor Cells (CTCs) Using Dual-Antibody-Modified Fluorescent-Magnetic Nanoparticles

Extreme rarity and inherent heterogeneity of circulating tumor cells (CTCs) result in a tremendous challenge for the CTC isolation from patient blood samples with high efficiency and purity. Current CTC isolation approaches mainly rely on the epithelial cell adhesion molecule (EpCAM), which may significantly reduce the ability to capture CTCs when the expression of EpCAM is lost or down-regulated in epithelial-mesenchymal transition. Here, a rapid and highly efficient method is developed to isolate and identify heterogeneous CTCs with high efficiency from patient blood samples using the fluorescent-magnetic nanoparticles (F-MNPs). A dual-antibody interface targeting EpCAM and N-cadherin is fabricated onto the F-MNPs to capture epithelial CTCs as well as mesenchymal CTCs from whole blood samples. The poly(carboxybetaine methacrylate) brushes of excellent antifouling properties are employed to decrease nonspecific cell adhesion. Moreover, the F-MNPs provide a prompt identification strategy for heterogeneous CTCs (F-MNPs+, Hoechst 33342+, and CD45-) that can directly identify CTCs in a gentle one-step processing within 1 h after isolation from patient blood samples. This has been demonstrated through artificial samples as well as patient samples in details.