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Biomedical Microdevices

Renna Qiu, Feng Qian, Xiaofeng Wang, Hongjun Li, Lizhe Wang
Colorectal cancer (CRC) is a major malignancy characterized by a high metastasis rate. Systematic chemotherapy is important for patients with advanced CRC. However, many limitations (e.g., side effects to normal organs, shorter circulation time, and unsatisfactory tumor inhibition results) of traditional chemotherapy restrict its further application. Thus, it is necessary to find a method to overcome these challenges and improve the efficacy of CRC treatment. In this study, 20(S)-ginsenoside (Rg3) co-loaded poly(ethylene glycol)-block-poly(L-glutamic acid-co-L-phenylalanine) (mPEG-b-P(Glu-co-Phe)) nanoparticles (Rg3-NPs) were prepared...
February 20, 2019: Biomedical Microdevices
Didi She, Melissa Tsang, Mark Allen
Biodegradable batteries play an important role in fully degradable biomedical or environmental systems. The development of biodegradable batteries faces many challenges including power content, device compactness, performance stability, shelf and functional lifetime. In particular, a key driver in the lifetime and overall size of microfabricated biodegradable batteries is the liquid electrolyte volume. Harnessing liquid from the environment to serve as the battery electrolyte may, therefore, be desirable; however, for stable operation, maintaining a constant electrochemical environment inside the cell is required even in the presence of changing body or environmental conditions...
February 12, 2019: Biomedical Microdevices
Ulri N Lee, Jean Berthier, Jiaquan Yu, Erwin Berthier, Ashleigh B Theberge
We present an open microfluidic platform that enables stable flow of an organic solvent over an aqueous solution. The device features apertures connecting a lower aqueous channel to an upper solvent compartment that is open to air, enabling easy removal of the solvent for analysis. We have previously shown that related open biphasic systems enable steroid hormone extraction from human cells in microscale culture and secondary metabolite extraction from microbial culture; here we build on our prior work by determining conditions under which the system can be used with extraction solvents of ranging polarities, a critical feature for applying this extraction platform to diverse classes of metabolites...
February 12, 2019: Biomedical Microdevices
Jingyi Wang, Niandong Jiao, Xiaodong Wang, Daojing Lin, Steve Tung, Lianqing Liu
Female anglerfishes have a lantern-shape luminous organ sprouting from the middle of their heads to lure their prey in the dark deep sea. Inspired by the anglerfish, we designed an electromagnetic anglerfish-shaped millirobot that can receive energy and transform it into light to attract algae cells to specific locations. The small wireless powered robot can receive about 658 mW of power from external energy supply coils, and light LEDs (light-emitting diodes). The wireless power generation and moving control of the robot are analyzed systematically...
February 11, 2019: Biomedical Microdevices
Chandana Kolluru, Mikayla Williams, Jihee Stephanie Yeh, Richard K Noel, Jennifer Knaack, Mark R Prausnitz
Minimally invasive point-of-care diagnostic devices are of great interest for rapid detection of biomarkers in diverse settings. Although blood is the most common source of biomarkers, interstitial fluid (ISF) is an alternate body fluid that does not clot or contain red blood cells that often complicate analysis. However, ISF is difficult to collect. In this study, we assessed the utility of a microneedle patch to sample microliter volumes of ISF in a simple and minimally invasive manner. We demonstrated the use of ISF collected in this way for therapeutic drug monitoring by showing similar vancomycin pharmacokinetic profiles in ISF and serum from rats...
February 6, 2019: Biomedical Microdevices
Levy I Amar, Michael I Hill, Monica Faria, Daniela Guisado, Cees J M van Rijn, Edward F Leonard
Steady state crossflow microfiltration (CMF) is an important and often necessary means of particle separation and concentration for both industrial and biomedical processes. The factors controlling the performance of CMF have been extensively reviewed. A major factor is transmembrane pressure (TMP). Because microchannels have small height, they tend to have high pressure gradients in the feed-flow direction. In the extreme, these gradients may even reverse the pressure across the membrane (inciting backflow)...
February 6, 2019: Biomedical Microdevices
Zhiyuan Huang, Xiong Liang, Chuntao Chang, Jiang Ma
Micro components processed by injection molding still have a defect of bad precision and short life. A Zr- based metallic glass was reported for injection mold insert which can solve the problem well. The microstructure of metallic glass mold insert can be fabricated by wire electrical discharge machining-low speed (WEDM-LS), WEDM-LS has higher machining accuracy than WEDM-high speed, and X-ray diffraction curves show that the processed sample still retained better amorphous characteristic, afterward, time-temperature-transformation diagram shows metallic glass has a long service life in production...
February 6, 2019: Biomedical Microdevices
G Marchi, P Foehr, S Consalvo, A Javadzadeh-Kalarhodi, J Lang, B Hartmann, P Alberton, A Aszodi, R Burgkart, J Roths
In this study, the capability of a fiber optic microindenter sensor to discriminate between healthy and slightly degenerated human articular cartilage samples is demonstrated. The purely optical indenter sensor is characterized by extremely reduced dimensions (0.125 mm in diameter and 27 mm in length) in comparison to existing indenter probes offering advantages for endoscopic deployment. The indenter sensor is intended to assist the surgeon in the identification of damaged articular cartilage. From each of seven specimens of human tibia plateau three samples showing different Outerbridge grading were extracted...
January 18, 2019: Biomedical Microdevices
Yuan Dai, A Abiri, J Pensa, S Liu, O Paydar, H Sohn, S Sun, P A Pellionisz, C Pensa, E P Dutson, W S Grundfest, R N Candler
The number of procedures performed with robotic surgery may exceed one million globally in 2018. The continual lack of haptic feedback, however, forces surgeons to rely on visual cues in order to avoid breaking sutures due to excessive applied force. To mitigate this problem, the authors developed and validated a novel grasper-integrated system with biaxial shear sensing and haptic feedback to warn the operator prior to anticipated suture breakage. Furthermore, the design enables facile suture manipulation without a degradation in efficacy, as determined via measured tightness of resulting suture knots...
January 10, 2019: Biomedical Microdevices
Alexander K Nguyen, Kai-Hung Yang, Kelsey Bryant, Junan Li, April C Joice, Karl A Werbovetz, Roger J Narayan
Current therapeutic options against cutaneous leishmaniasis are plagued by several weaknesses. The effective topical delivery of an antileishmanial drug would be useful in treating some forms of cutaneous leishmaniasis. Toward this end, a microneedle based delivery approach for the antileishmanial drug amphotericin B was investigated in murine models of both New World (Leishmania mexicana) and Old World (Leishmania major) infection. In the L. mexicana model, ten days of treatment began on day 35 post infection, when the area of nodules averaged 9-15 mm2 ...
January 7, 2019: Biomedical Microdevices
Liang Wan, Jie Gao, Tianlan Chen, Cheng Dong, Haoran Li, Yan-Zi Wen, Zhao-Rong Lun, Yanwei Jia, Pui-In Mak, Rui P Martins
A major goal in the development of point-of-care (POC) devices is to build them as portable to provide a rapid and effective determination for disease pathogens. In nucleic acid testing, an optical detection system used to monitor the product of nucleic acid amplification has always been a bulky accessory. In this work, we developed a handheld, automatic and detection system-free thermal digital microfluidic (DMF) device for DNA detection by loop-mediated isothermal amplification (LAMP). Droplet manipulation and real-time temperature control systems were integrated into a handheld device...
January 7, 2019: Biomedical Microdevices
Yiren Shen, Kun Du, Lili Zou, Xiaoming Zhou, Rong Lv, Dayong Gao, Bensheng Qiu, Weiping Ding
Freeze-drying is a promising approach for the long-term storage of erythrocytes at room temperature. Studies have shown that trehalose loaded into erythrocytes plays an important role in protecting erythrocytes against freeze-drying damage. Due to the impermeability of the erythrocyte membrane to trehalose, many methods have been developed to load trehalose into erythrocytes. However, these methods usually require multistep manual manipulation and long processing time; the adopted protocols are also diverse and not standardized...
January 3, 2019: Biomedical Microdevices
Yan Shi, Qian Wu, Dongyang Sun, Cunfa Gao
Microfluidics shows a great importance in fluid control in biomedicine area. Recently, a programmable soft microfluidic system for applications of pharmacology and optogenetics is reported in Cell. Based on the theory of thermal expansion, we established an analytic model to characterize the injection process of the microfluidic systems. Finite element analyses (FEA) were employed to validate this model. The comparison between the analytic model and FEA well demonstrates the practicality of the analytic model...
January 3, 2019: Biomedical Microdevices
Wentao Dong, Xiao Cheng, Tao Xiong, Xiaoming Wang
Current stretchable surface electrodes have attracted more and more attentions owing to their potential applications in the fields of biological signal monitoring, wearable human-machine interface (HMI) and Internet of Things (IoT). The paper presents that stretchable bio-potential electrode is designed with the second order self-similar serpentine structure to continuous, long-term, stable ECG signal recordings which is conformal contact with the soft skin surface. FEM and experiments have validated >30% deformability of the surface electrode with second order self-similar structure...
January 3, 2019: Biomedical Microdevices
Yu-Hsiang Hsu, Wei-Wen Liu, Tung-Han Wu, Carina Jean-Tien Lee, Yu-Hsi Chen, Pai-Chi Li
In this paper, we report on using mass transport to control nutrition supply of colorectal cancer cells for developing a microtumor in a confined microchamber. To mimic the spatial heterogeneity of a tumor, two microfluidic configurations based on resistive circuits are designed. One has a convection-dominated microchamber to simulate the tumor region proximal to leaky blood vessels. The other has a diffusion-dominated microchamber to mimic the tumor core that lacks blood vessels and nutrient supply. Thus, the time for nutrition to fill the microchamber can vary from tens of minutes to several hours...
January 3, 2019: Biomedical Microdevices
Paridhi Puri, Vijay Kumar, S U Belgamwar, N N Sharma
Dielectrophoresis (DEP) devices have proven to be one of the most promising tools to transport, accumulate and sort various cells and particles. The major challenge in the development of DEP devices is the high cost, low yield using Microelectromechanical systems (MEMS). In this paper, we demonstrate a facile, low-cost, and high-throughput method of constructing continuous-flow DEP devices using screen-printing technology. Much literature has concluded that the use of carbon electrodes provides more cost effective and more durable DEP devices than metal electrodes...
December 10, 2018: Biomedical Microdevices
Megan N Kelchen, Nicole K Brogden
Topical beta-blocker formulations are commonly used to treat infantile hemangiomas (IHs); however, the skin concentrations and drug permeation through the skin have not been quantified. Microneedles (MNs) may increase local skin concentrations, which could further enhance lesion clearance and improve dosing regimens. The objective of this study was to quantify skin concentrations and drug permeation of two beta-blockers, propranolol and timolol, in vitro after application to intact skin and skin pretreated with solid MNs of two lengths...
December 6, 2018: Biomedical Microdevices
Federico Ribet, Göran Stemme, Niclas Roxhed
Continuous glucose monitoring (CGM) has the potential to greatly improve diabetes management. The aim of this work is to show a proof-of-concept CGM device which performs minimally invasive and minimally delayed in-situ glucose sensing in the dermal interstitial fluid, combining the advantages of microneedle-based and commercially available CGM systems. The device is based on the integration of an ultra-miniaturized electrochemical sensing probe in the lumen of a single hollow microneedle, separately realized using standard silicon microfabrication methods...
December 6, 2018: Biomedical Microdevices
Alexander M Saucedo, Jorge De La Cerda, Hiroo Suami, Rita E Serda
Beyond heterogeneous cancer cells, the tumor microenvironment includes stromal and immune cells, blood vessels, extracellular matrix and biologically active molecules. Abnormal signaling, uncontrolled proliferation and high interstitial pressure all contribute to a chaotic, non-hierarchical vascular organization. Using an immune competent 4T1 breast adenocarcinoma murine model, this study fully characterizes the architecture and immunocyte milieu of the tumor microenvironment. Heterogeneous vessel distribution, chaotic connectivity, limited perfusion, cancer cell density, immune phenotype, and biological responses to immune therapy are presented...
December 3, 2018: Biomedical Microdevices
Wenwen Li, Changyue Sun, Songlin Yu, Zhihua Pu, Penghao Zhang, Kexin Xu, Zhenqiang Song, Dachao Li
This paper proposes a novel fiber attenuated total reflection (ATR) sensor with silver nanoparticles (AgNPs) on the flattened structure based on mid-infrared spectroscopy for detecting low concentration of glucose with high precision. The flattened structure was designed to add the effective optical path length to improve the sensitivity. AgNPs were then deposited on the surface of the flattened area of the fiber via chemical silver mirror reaction for further improving the sensitivity by enhancing the infrared absorption...
November 23, 2018: Biomedical Microdevices
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