Time-traceable micro-taggants for anti-counterfeiting and secure distribution of food and medicines.

This study presents an innovative solution for the enhanced tracking and security of pharmaceuticals through the development of microstructures incorporating environmentally responsive, coded microparticles. Utilizing maskless photolithography, we engineered these microparticles with a degradable masking layer with 30 µm thickness that undergoes controlled dissolution. Quantitative analysis revealed that the protective layer's degradation, monitored by red fluorescence intensity, diminishes predictably over 144 h in phosphate-buffered saline under physiological conditions. This degradation not only confirms the microparticles' integrity but also allows the extraction of encoded information, which can serve as a robust indicator of medicinal shelf life and a deterrent to tampering. These findings indicate the potential for applying this technology in real-time monitoring of pharmaceuticals, ensuring quality and authenticity in the supply chain.

Optimizing Binding Site Spacing in Fluidic Self-Assembly for Enhanced Microchip Integration Density.

This manuscript presents a comprehensive study on the assembly of microchips using fluidic self-assembly (FSA) technology, with a focus on optimizing the spacing between binding sites to improve yield and assembly. Through a series of experiments, we explored the assembly of microchips on substrates with varying binding site spacings, revealing the impact of spacing on the rate of undesired chip assembly across multiple sites. Our findings indicate a significant reduction in incorrect assembly rates as the spacing increases beyond a critical threshold of 140 µm. This study delves into the mechanics of chip alignment within the fluid medium, hypothesizing that the extent of the alloy's grip on the chips at different spacings influences assembly outcomes. By analyzing cases of undesired assembly, we identified the relationship between binding site spacing and the area of chip contact, demonstrating a decrease in the combined left and right areas of chips as the spacing increases. The results highlight a critical spacing threshold, which, when optimized, could significantly enhance the efficiency and precision of microchip assembly processes using FSA technology. This research contributes to the field of microcomponent assembly, offering insights into achieving higher integration densities and precision in applications, such as microLED displays and augmented reality (AR) devices.

Implantable Self-Reporting Stents for Detecting In-Stent Restenosis and Cardiac Functional Dynamics.

Despite the increasing number of stents implanted each year worldwide, patients remain at high risk for developing in-stent restenosis. Various self-reporting stents have been developed to address this challenge, but their practical utility has been limited by low sensitivity and limited data collection. Herein, we propose a next-generation self-reporting stent that can monitor blood pressure and blood flow inside the blood arteries. This proposed self-reporting stent utilizes a larger inductor coil encapsulated on the entire surface of the stent strut, resulting in a 2-fold increase in the sensing resolution and coupling distance between the sensor and external antenna. The dual-pressure sensors enable the detection of blood flow in situ. The feasibility of the proposed self-reporting stent is successfully demonstrated through in vivo analysis in rats, verifying its biocompatibility and multifunctional utilities. This multifunctional self-reporting stent has the potential to greatly improve cardiovascular care by providing real-time monitoring and unprecedented insight into the functional dynamics of the heart.

Correction: Quantitative assessment of cardiomyocyte mechanobiology through high-throughput cantilever-based functional well plate systems.

Correction for 'Quantitative assessment of cardiomyocyte mechanobiology through high-throughput cantilever-based functional well plate systems' by Jongyun Kim et al., Analyst, 2023, 148, 5133-5143, https://doi.org/10.1039/D3AN01286G.

Quantitative assessment of cardiomyocyte mechanobiology through high-throughput cantilever-based functional well plate systems.

Proper regulation of the in vitro cell culture environment is essential for disease modelling and drug toxicity screening. The main limitation of well plates used for cell culture is that they cannot accurately maintain energy sources and compounds needed during cell growth. Herein, to understand the importance of perfusion in cardiomyocyte culture, changes in contractile force and heart rate during cardiomyocyte growth are systematically investigated, and the results are compared with those of a perfusion-free system. The proposed perfusion system consists of a Peltier refrigerator, a peristaltic pump, and a functional well plate. A functional well plate with 12 wells is made through injection moulding, with two tubes integrated in the cover for each well to continuously circulate the culture medium. The contractile force of cardiomyocytes growing on the cantilever surface is analysed through changes in cantilever displacement. The maturation of cardiomyocytes is evaluated through fluorescence staining and western blot; cardiomyocytes cultured in the perfusion system show greater maturity than those cultured in a manually replaced culture medium. The pH of the culture medium manually replaced at intervals of 3 days decreases to 6.8, resulting in an abnormal heartbeat, while cardiomyocytes cultured in the perfusion system maintained at pH 7.4 show improved contractility and a uniform heart rate. Two well-known ion channel blockers, verapamil and quinidine, are used to measure changes in the contractile force of cardiomyocytes from the two systems. Cardiomyocytes in the perfusion system show greater stability during drug toxicity screening, proving that the perfusion system provides a better environment for cell growth.

Rapid remodeling observed at mid-term in-vivo study of a smart reinforced acellular vascular graft implanted on a rat model.

BACKGROUND: The poor performance of conventional techniques used in cardiovascular disease patients requiring hemodialysis or arterial bypass grafting has prompted tissue engineers to search for clinically appropriate off-the-shelf vascular grafts. Most patients with cardiovascular disease lack suitable autologous tissue because of age or previous surgery. Commercially available vascular grafts with diameters of < 5 mm often fail because of thrombosis and intimal hyperplasia. RESULT: Here, we tested tubular biodegradable poly-e-caprolactone/polydioxanone (PCL/PDO) electrospun vascular grafts in a rat model of aortic interposition for up to 12 weeks. The grafts demonstrated excellent patency (100%) confirmed by Doppler Ultrasound, resisted aneurysmal dilation and intimal hyperplasia, and yielded neoarteries largely free of foreign materials. At 12 weeks, the grafts resembled native arteries with confluent endothelium, synchronous pulsation, a contractile smooth muscle layer, and co-expression of various extracellular matrix components (elastin, collagen, and glycosaminoglycan). CONCLUSIONS: The structural and functional properties comparable to native vessels observed in the neoartery indicate their potential application as an alternative for the replacement of damaged small-diameter grafts. This synthetic off-the-shelf device may be suitable for patients without autologous vessels. However, for clinical application of these grafts, long-term studies (> 1.5 years) in large animals with a vasculature similar to humans are needed.

I-LIFT (image-based laser-induced forward transfer) platform for manipulating encoded microparticles.

Encoded microparticles have great potential in small-volume multiplexed assays. It is important to link the micro-level assays to the macro-level by indexing and manipulating the microparticles to enhance their versatility. There are technologies to actively manipulate the encoded microparticles, but none is capable of directly manipulating the encoded microparticles with homogeneous physical properties. Here, we report the image-based laser-induced forward transfer system for active manipulation of the graphically encoded microparticles. By demonstrating the direct retrieval of the microparticles of interest, we show that this system has the potential to expand the usage of encoded microparticles.

Stress induced self-rollable smart-stent-based U-health platform for in-stent restenosis monitoring.

To date, several smart stents have been proposed to continuously detect biological cues, which is essential for tracking patients' critical vital signs and therapy. However, the proposed smart stent fabrication techniques rely on conventional laser micro-cutting or 3D printing technologies. The sensors are then integrated into the stent structure using an adhesive, conductive epoxy, or laser micro-welding process. The sensor packaging method using additional fabrication processes can cause electrical noise, and there is a possibility of sensor detachment from the sent structure after implantation, which may pose a significant risk to patients. Herein, we are demonstrating for the first time a single-step fabrication method to develop a smart stent with an integrated sensor for detecting in-stent restenosis and assessing the functional dynamics of the heart. The smart stent is fabricated using a microelectromechanical system (MEMS)-based micromachining technology. The proposed smart stent can detect biological cues without additional power and wirelessly transmit the signal to the network analyzer. The cytocompatibility of the smart stent is confirmed through a cytotoxicity test by monitoring the cell growth, proliferation, and viability of the cultured cardiomyocytes. The capacitance of the smart stent exhibits an excellent linear relationship with the applied pressure. The exceptional sensitivity of the pressure sensor enabled the proposed smart stent to detect biological cues during in vivo analysis. The preliminary findings confirmed the proposed smart stent's higher level of structural integrity, durability and repeatability. Finally, the practical feasibility of the smart stent is demonstrated by monitoring diastole and systole at various beat rates using a phantom. The results of the phantom study showed a similar pattern to the human model, indicating the potential use of the proposed multifunctional smart stent for real-time applications.

MEA-integrated cantilever platform for comparison of real-time change in electrophysiology and contractility of cardiomyocytes to drugs.

Drug-induced cardiotoxicity is a potentially severe side effect that can alter the contractility and electrophysiology of the cardiomyocytes. Cardiotoxicity is generally assessed through animal models using conventional drug screening platforms. Despite significant developments in drug screening platforms, the difficulty in measuring electrophysiology and contractile profile together affects the investigation of cardiotoxicity in potential drugs. Some drugs can prove to be more toxic to contractility than electrophysiology, which demands the need for a reliable, dual, and simultaneous drug screening platform. Herein, we propose the microelectrode array integrated SU-8 cantilever for dual and simultaneous measurement of electrophysiology and contractility of cardiomyocytes. The SU-8 cantilever is integrated with microelectrode array (C-MEA) using conventional photolithographic techniques. Drug tests are conducted to verify the feasibility of the C-MEA platform using three cardiovascular drugs. Clinically recognized drugs, quinidine and verapamil, are used to activate both the hERG channel and the contractile characteristics of cardiomyocytes. The effect of ion channel blockers on the field potential duration (FPD) of the cardiomyocytes is compared with several contractility-based parameters. The contraction-relaxation duration (CRD) profile is relatively close to that of FPD in tested drugs (half-maximal (IC50) toxicities are 1.093 µM (FPD) and 1.924 µM (CRD) for quinidine and 166.2 nM (FPD) and 459.4 nM (CRD) for verapamil). Blebbistatin, a known myosin II inhibitor, primarily affects the contractile profile of cardiomyocytes but not their field potential, with no evident correlation between contractility and field potential profiles. The proposed cantilever-based mechano-electrophysiology measurements platform provides a promising and accurate means to assess cardiotoxicity.

A Comparative Study of an Anti-Thrombotic Small-Diameter Vascular Graft with Commercially Available e-PTFE Graft in a Porcine Carotid Model.

BACKGROUND: We have designed a reinforced drug-loaded vascular graft composed of polycaprolactone (PCL) and polydioxanone (PDO) via a combination of electrospinning/3D printing approaches. To evaluate its potential for clinical application, we compared the in vivo blood compatibility and performance of PCL/PDO + 10%DY grafts doped with an antithrombotic drug (dipyridamole) with a commercial expanded polytetrafluoroethylene (e-PTFE) graft in a porcine model. METHODS: A total of 10 pigs (weight: 25-35 kg) were used in this study. We made a new 5-mm graft with PCL/PDO composite nanofiber via the electrospinning technique. We simultaneously implanted a commercially available e-PTFE graft (n = 5) and our PCL/PDO + 10%DY graft (n = 5) into the carotid arteries of the pigs. No anticoagulant/antiplatelet agent was administered during the follow-up period, and ultrasonography was performed weekly to confirm the patency of the two grafts in vivo. Four weeks later, we explanted and compared the performance of the two grafts by histological analysis and scanning electron microscopy (SEM). RESULTS: No complications, such as sweating on the graft or significant bleeding from the needle hole site, were seen in the PCL/PDO + 10%DY graft immediately after implantation. Serial ultrasonographic examination and immunohistochemical analysis demonstrated that PCL/PDO + 10%DY grafts showed normal physiological blood flow and minimal lumen reduction, and pulsed synchronously with the native artery at 4 weeks after implantation. However, all e-PTFE grafts occluded within the study period. The luminal surface of the PCL/PDO + 10%DY graft in the transitional zone was fully covered with endothelial cells as observed by SEM. CONCLUSION: The PCL/PDO + 10%DY graft was well tolerated, and no adverse tissue reaction was observed in porcine carotid models during the short-term follow-up. Colonization of the graft by host endothelial and smooth muscle cells coupled with substantial extracellular matrix production marked the regenerative capability. Thus, this material may be an ideal substitute for vascular reconstruction and bypass surgeries. Long-term observations will be necessary to determine the anti-thrombotic and remodeling potential of this device.

Multi-layered polymer cantilever integrated with full-bridge strain sensor to enhance force sensitivity in cardiac contractility measurement.

In this study, we developed a multi-layered functional cantilever for real-time force measurement of cardiomyocytes in cell culture media. The functional cantilever with a full-bridge circuit configuration was composed of one polydimethylsiloxane (PDMS) and two polyimide (PI) layers, forming two resistive sensors on each upper side of the two PI layers. The PI layers were chemically bonded using an oxygen plasma treatment, with a thin composite layer consisting of Cr/SiO2/PDMS. These greatly improved the force sensitivity and the long-term reliability of the integrated strain sensor operating in liquids. The nanogrooved PDMS top layer bonded on the upper PI layer was employed to further improve the growth of cardiomyocytes on the functional cantilever. The difference in resistance changes and response characteristics was confirmed by evaluating the characteristics of the multi-layered polymer cantilevers with half-bridge and full-bridge circuit configurations. We also employed the cantilever devices to measure the contraction force of cardiomyocytes for 16 days and side effects in real time in human-induced pluripotent stem cells treated with the cardiovascular drug verapamil. The sensor-integrated cantilever devices are expected to be utilized as a novel biomedical sensor for evaluating the mechanobiology of cardiomyocytes, as well as in drug screening tests.

Color-Coded Droplets and Microscopic Image Analysis for Multiplexed Antibiotic Susceptibility Testing.

Since the discovery of antibiotics, the emergence of antibiotic resistance has become a global issue that is threatening society. In the era of antibiotic resistance, finding the proper antibiotics through antibiotic susceptibility testing (AST) is crucial in clinical settings. However, the current clinical process of AST based on the broth microdilution test has limitations on scalability to expand the number of antibiotics that are tested with various concentrations. Here, we used color-coded droplets to expand the multiplexing of AST regarding the kind and concentration of antibiotics. Color type and density differentiate the kind of antibiotics and concentration, respectively. Microscopic images of a large view field contain numbers of droplets with different testing conditions. Image processing analysis detects each droplet, decodes color codes, and measures the bacterial growth in the droplet. Testing E. coli ATCC 25922 with ampicillin, gentamicin, and tetracycline shows that the system can provide a robust and scalable platform for multiplexed AST. Furthermore, the system can be applied to various drug testing systems, which require several different testing conditions.

Photopatterned microswimmers with programmable motion without external stimuli.

We introduce highly programmable microscale swimmers driven by the Marangoni effect (Marangoni microswimmers) that can self-propel on the surface of water. Previous studies on Marangoni swimmers have shown the advantage of self-propulsion without external energy source or mechanical systems, by taking advantage of direct conversion from power source materials to mechanical energy. However, current developments on Marangoni microswimmers have limitations in their fabrication, thereby hindering their programmability and precise mass production. By introducing a photopatterning method, we generated Marangoni microswimmers with multiple functional parts with distinct material properties in high throughput. Furthermore, various motions such as time-dependent direction change and disassembly of swimmers without external stimuli are programmed into the Marangoni microswimmers.

64 PI/PDMS hybrid cantilever arrays with an integrated strain sensor for a high-throughput drug toxicity screening application.

Herein, we propose a novel biosensing platform involving an array of 64 hybrid cantilevers and integrated strain sensors to measure the real-time contractility of the drug-treated cardiomyocytes (CMs). The strain sensor is integrated on the polyimide (PI) cantilever. To improve the strain sensor reliability and construct the engineered cardiac tissue, the nanogroove-patterned polydimethylsiloxane (PDMS) encapsulation layer is bonded on the PI cantilever. The preliminary sensing characteristics demonstrate the superior structural integrity, robustness, enhanced sensitivity, and repeatability of the proposed devices. The long-term durability and biocompatibility of the PI/PDMS hybrid cantilever is verified by evaluating the cell viability and contractility. We also validate the proposed biosensing platform for cardiotoxicity measurement by applying it to two specific cardiovascular drugs: quinidine and verapamil. In response to quinidine and verapamil, the engineered CMs exhibited negative inotropic and chronotropic effects. The fabricated cantilever device successfully detected the quinidine-induced adverse effects in CMs such as early after depolarization (EADs) and Torsade de points (TdP) in real-time. The array of hybrid cantilevers with integrated strain sensors has the potential to satisfy the need for innovative analytic platforms owing to its high throughput and simplified data analysis.

Nasopharyngeal Type-I Interferon for Immediately Available Prophylaxis Against Emerging Respiratory Viral Infections.

In addition to SARS-CoV-2 and its variants, emerging viruses that cause respiratory viral infections will continue to arise. Increasing evidence suggests a delayed, possibly suppressed, type 1 interferon (IFN-I) response occurs early during COVID-19 and other viral respiratory infections such as SARS and MERS. These observations prompt considering IFN-ß as a prophylactic or early intervention for respiratory viral infections. A rationale for developing and testing intranasal interferon beta (IFN-ß) as an immediately available intervention for new respiratory viral infections that will arise unexpectedly in the future is presented and supported by basic and clinical trial observations. IFN-ß prophylaxis could limit the spread and consequences of an emerging respiratory viral infection in at-risk individuals while specific vaccines are being developed.

Direct 2D-to-3D transformation of pen drawings.

Pen drawing is a method that allows simple, inexpensive, and intuitive two-dimensional (2D) fabrication. To integrate such advantages of pen drawing in fabricating 3D objects, we developed a 3D fabrication technology that can directly transform pen-drawn 2D precursors into 3D geometries. 2D-to-3D transformation of pen drawings is facilitated by surface tension-driven capillary peeling and floating of dried ink film when the drawing is dipped into an aqueous monomer solution. Selective control of the floating and anchoring parts of a 2D precursor allowed the 2D drawing to transform into the designed 3D structure. The transformed 3D geometry can then be fixed by structural reinforcement using surface-initiated polymerization. By transforming simple pen-drawn 2D structures into complex 3D structures, our approach enables freestyle rapid prototyping via pen drawing, as well as mass production of 3D objects via roll-to-roll processing.

Gradient-Wrinkled Microparticle with Grayscale Lithography Controlling the Cross-Linking Densities for High Security Level Anti-Counterfeiting Strategies.

Physical unclonable functions (PUFs) enable different characteristics according to the purpose, such as easy to access identification, high security level, and high code capacity, against counterfeiting a product. However, most multiplex approaches have been implemented by embedding several security features rather than one feature. In this paper, we present a high security level anti-counterfeiting strategy using only labyrinth wrinkle patterns with different complexities, which can be used as unique and unclonable codes. To generate codes with different levels in a microtaggant, we fabricated wrinkle patterns with characteristic wavelength gradients using grayscale lithography. The elastic modulus of the polymer substrate and corresponding wavelength after the wrinkling process were controlled by designing the gray level of each subcode region in a gray-level mask image for photopolymerization of the microparticle substrate. We then verified the uniqueness of the extracted minutia codes through a cross-correlation analysis. Finally, we demonstrated the authentication strategies by decoding different minutia codes according to the scanning resolution during the decoding. Overall, the presented patterning method can be widely used in security code generation.

On-stage bioreactor platform integrated with nano-patterned and gold-coated PDMS diaphragm for live cell stimulation and imaging.

Over the years, several in-vitro biosensing platforms have been developed for enhancing the maturation of the cultured cells. However, most of the proposed platforms met with limited success due to its inability for live-cell imaging, complicated fabrication, and not being advantageous from an economic perspective due to a higher price. To overcome the drawbacks of the current state-of-the-art, herein, we developed a next-generation stage-top incubator (STI) incorporated with nano grooves patterned PDMS diaphragm (NGPPD). The proposed device consists of a miniatured STI, the NGPPD functional well plates, and a mechanical stimulator. A thin layer of gold (Au) is deposited on the NGPPD to enhanced myogenic differentiation, cell maturation, and cell-cell interactions. The nano grooves are integrated on the PDMS surface to align the cardiomyocytes in the grooved direction during the culture period. The cardiomyocytes cultivated on the Au-deposited NGPPD are stimulated topographically and mechanically during the cultivation period. The enhanced cardiomyocytes maturation cultured on the Au-deposited NGPPD is experimentally demonstrated using immunofluorescence staining and PCR analysis.

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.

Microspinning: Local Surface Mixing via Rotation of Magnetic Microparticles for Efficient Small-Volume Bioassays.

The need for high-throughput screening has led to the miniaturization of the reaction volume of the chamber in bioassays. As the reactor gets smaller, surface tension dominates the gravitational or inertial force, and mixing efficiency decreases in small-scale reactions. Because passive mixing by simple diffusion in tens of microliter-scale volumes takes a long time, active mixing is needed. Here, we report an efficient micromixing method using magnetically rotating microparticles with patterned magnetization induced by magnetic nanoparticle chains. Because the microparticles have magnetization patterning due to fabrication with magnetic nanoparticle chains, the microparticles can rotate along the external rotating magnetic field, causing micromixing. We validated the reaction efficiency by comparing this micromixing method with other mixing methods such as simple diffusion and the use of a rocking shaker at various working volumes. This method has the potential to be widely utilized in suspension assay technology as an efficient mixing strategy.