Highly Integrated Cell-Imprinted Biomimetic Interface for All-in-One Diagnosis of Heterogeneous Circulating Tumor Cells

Significantly enhanced capture efficiency of cell-imprinted material for circulating tumor cells via a flexible and ultra-strong double-armed phenylboronic acid design

Circulating tumor cells (CTC) have been incontrovertibly regarded as a critically essential detection tool within the realm of cancer combat, being decidedly preferred by oncology clinicians and serving as the preponderant primary targets for single-cell analysis. However, several challenges hinder the effective capture of CTC from blood, including their rarity, heterogeneity across cancer types, the complexity of the blood environment, and potential damage to cell viability. Here we design a flexible double-armed phenylboric acid (DPBA) that targets double-branched sialylated glycans (SGs) on the surface of liver CTC. The binding affinity of DPBA (200 nM) is 33 times greater than that of typical phenylboric acid, as confirmed by glycoproteomics analysis demonstrating a strong prevalence for SGs. By copolymerization of DPBA with polyethylene glycol dimethacrylate (PEGDMA), using SMMC-7721 cells as templates, we developed a cell-imprinted hydrogel featuring compact polymeric networks interconnected by both chemical crosslinking and hydrogen bonding. This hydrogel exhibits an ultra-low swelling capacity of 5 %, effectively preserving the nano- and micro-morphologies of cell imprinting. It also demonstrates low protein adhesion, appropriate elasticity and reversibility, as well as satisfactory blood and cell compatibility. The high affinity for double-branched SGs and clear cell imprinting endow the material with precise capture efficiency for CTC, enabling accurate discrimination between liver cancer patients and healthy individuals, with an excellent area under the curve (AUC) of 0.99 and a high classification accuracy of 96 %. Importantly, the captured CTC could be released alive for genomics analysis. The material costs just 1.98 dollars per sample, which is only 1/200th of the typical medical price. This study highlights the significant potential of flexible double-armed molecular design in the development of CTC capture materials, which will promote downstream single-cell multi-proteomics analysis and facilitate early cancer diagnostics.

ECL cytosensor for sensitive and label-free detection of circulating tumor cells based on hierarchical flower-like gold microstructures

The development of sensitive and efficient cell sensing strategies to detect circulating tumor cells (CTCs) in peripheral blood is crucial for the early diagnosis and prognostic assessment of cancer clinical treatment. Herein, an array of hierarchical flower-like gold microstructures (HFGMs) with anisotropic nanotips was synthesized by a simple electrodeposition method and used as a capture substrate to construct an ECL cytosensor based on the specific recognition of target cells by aptamers. The complex topography of the HFGMs array not only catalyzed the enhancement of ECL signals, but also induced the cells to generate more filopodia, improving the capture efficiency and shortening the capture time. The effect of topographic roughness on cell growth and adhesion propensity was also investigated, while the cell capture efficiency was proposed to be an important indicator affecting the accuracy of the ECL cytosensor. In addition, the capture of cells on the electrode surface increased the steric hindrance, which caused ECL signal changes in the Ru(bpy)32+ and TPrA system, realizing the quantitative detection of MCF-7 cells. The detection range of the sensor was from 102 to 106 cells mL-1 and the detection limit was 18 cells mL-1. The proposed detection method avoids the process of separation, labeling and counting, which has great potential for sensitive detection in clinical applications.

Improving performance of cell imprinted PDMS by integrating boronate affinity and local post-imprinting modification for selective capture of circulating tumor cells from cancer patients

Efficient capture of circulating tumor cells (CTCs) from cancer patients is an important technique that may promote early diagnosis and prognosis monitoring of cancer. However, the existing systems have certain disadvantages, such as poor selectivity, low capture efficiency, consumption of antibodies, and difficulty in release of CTCs for downstream analysis. Herein, we fabricated an innovative PEGylated boronate affinity cell imprinted polydimethylsiloxane (PBACIP) for highly efficient capture of CTCs from cancer patients. The antibody-free PBACIP possessed hierarchical structure of imprinted cavities, which were inlaid with boronic acid modified SiO₂ nanoparticles (SiO₂@BA), so it could specifically capture target CTCs from biological samples due to the synergistic effect of boronate affinity and cell imprinting. Furthermore, PEGylation was accurately completed in the non-imprinted region by the template cells occupying the imprinted cavity, which not only retained the microstructure of original imprinted cavities, but also endowed PBACIP with hydrophilicity. The artificial PBACIP could efficiently capture human breast-cancer cells from biological sample. When 5 to 500 SKBR3 cells were spiked in 1 mL mice lysed blood, the capture efficiency reached 86.7 ± 11.5% to 96.2 ± 2.3%. Most importantly, the PBACIP was successfully used to capture CTCs from blood of breast cancer patients, and the captured CTCs were released for subsequent gene mutation analysis. The PBACIP can efficiently capture and release CTCs for downstream analysis, which provides a universal strategy toward individualized anti-tumor comprehensive treatments and has great potential in the future cell-based clinical applications.

Greenificated Molecularly Imprinted Materials for Advanced Applications

Molecular imprinting technology (MIT) produces artificial binding sites with precise complementarity to substrates and thereby is capable of exquisite molecular recognition. Over five decades of evolution, it is predicted that the resulting host imprinted materials will overtake natural receptors for research and application purposes, but in practice, this has not yet been realized due to the unsustainability of their life cycles (i.e., precursors, creation, use, recycling, and end-of-life). To address this issue, greenificated molecularly imprinted polymers (GMIPs) are a new class of plastic antibodies that have approached sustainability by following one or more of the greenification principles, while also demonstrating more far-reaching applications compared to their natural counterparts. In this review, the most recent developments in the delicate design and advanced application of GMIPs in six fast-growing and emerging fields are surveyed, namely biomedicine/therapy, catalysis, energy harvesting/storage, nanoparticle detection, gas sensing/adsorption, and environmental remediation. In addition, their distinct features are highlighted, and the optimal means to utilize these features for attaining incredibly far-reaching applications are discussed. Importantly, the obscure technical challenges of the greenificated MIT are revealed, and conceivable solutions are offered. Lastly, several perspectives on future research directions are proposed.

Natural Tissue-Imprinted Biointerface for the Topographical Education of a Biomimetic Cell Sheet

Cell sheet engineering as a cell-based scaffold-free therapy is promising in tissue engineering, allowing precise transforming treatments for various tissue damage. However, the current cutting-edge techniques are still hampered by the difficulty in mimicking the natural tissue organizations and the corresponding physiological functions. In this work, cell-imprinting technology using the natural tissue as a template was proposed to rationally educate the cellular alignment in the cell sheet. Through this technique, we obtained temporary templates with morphological structure complementary to native tissues and then directly transferred the structure on the template to the collagen layer on a photothermally convertible substrate by secondary imprinting replication. The resultant biomimetic interface was used for cell culture and release to obtain a cell sheet with a texture similar to the natural tissue morphology. Different from conventional photolithography, the natural tissue-imprinted biointerface guides the geometry of cell sheets in the way of natural principles instead of stereotyped or overuniform cell organization. Simultaneously, a near-infrared laser (NIR) was used to irradiate the photothermally responsive substrate to obtain complete cell sheets efficiently and nondestructively. The natural tissue-educated myocardium cell sheets exhibited good physiological activity and biomimetic biofunctions, such as mechanical properties and physiological performances. This approach might open an inspiring prospect in regenerative medicine and offer a new approach to realizing the biomimetic tissue construction.

Antifouling Gold-Inlaid BSA Coating for the Highly Efficient Capture of Circulating Tumor Cells

Large amounts of coexisting contamination in complex biofluid samples impede the quantified veracity of biomarkers, which is the key problem for disease confirmation. Herein, amyloid-like transformed bovine serum albumin inlaid with gold nanoparticles was used as a coating (BGC) on a substrate composed of silicon nanowires (SW; BGC-SW) under ambient conditions. After modification with the recognition group, BGC-SW could serve as an outstanding platform for the selective separation and sensitive detection of biomarkers in complicated biosamples. First, the BGC on SW with a large surface area exhibits excellent adhesion resistance. The attached amounts of contaminations in biofluids were decreased by over 78% compared with native bovine serum albumin (BSA) as the blocking agent. This is because the phase-transformed BSA coating provides stronger interactions with the SW than bare BSA, which results in a tighter attachment and more uniform coverage of the BGC. Furthermore, the gold matrix laid inside the antiadhesive coating ensures simple cross-linking with the recognition groups to selectively capture various biomarkers in complex biofluids and create a gentle release method. Circulating tumor cells (CTCs) were chosen as template biomarkers to verify the application of A-BGC-SW (BGC-SW modified with sgc8-aptamer) in various separation processes of untreated biofluids. The results showed that approximately six cells could be captured from a 1 mL fresh blood sample containing only 10 CTCs. The easy fabrication and excellent antiadhesion property endow A-BGC-SW with great potential in the field of biological separation.