Comparison of the performance of the PANArray™ HPV test and DNA chip test for genotyping of human papillomavirus in cervical swabs

송혜정,이정원,김병기,송상용,배덕수,김대식 한국바이오칩학회 2010 BioChip Journal Vol.4 No.3

The aim of this study was to evaluate the recently developed PANArray™ Human papilloma virus (HPV) kit for detection and genotyping of 19 high-risk and 13 low-risk HPV types, and compare it with the commercially available DNA chip kit geno-typing of 24 HPVs. We llected cervical swabs from 741 patients with various stages of invasive cervical carcinoma being treated at the Samsung Medical Center. The overall HPV positivity rate was 73% using PANArray™ HPV and 72.1% with the DNA chip, and no statistically significant differences were found with respect to the cytology grade. Comparing the results of the two chips, concordant results were found in 637/741 samples (85.9%), compatible in 69/741 (9.3%) and discordant in 35/741(4.7%). Type-specific sequencing analysis of all samples revealed a 99.7% confirmation of PANArray™ HPV genotyping results, compared to 91.0% of DNA chip. The PANArray™ HPV test thus proved to be highly sensitive and accurate even when multiple HPV infections were present.

Fabrication of a Nanoplasmonic Chip to Enhance Neuron Membrane Potential Imaging by Metal-Enhanced Fluorescence Effect

김래영,남윤기 한국바이오칩학회 2021 BioChip Journal Vol.15 No.2

Optical imaging is a useful tool to acquire neural activities because of its high spatial resolution, and various voltage indicators were developed to image membrane potential of neurons. Voltage sensitive dyes (VSDs) are one of them but their signal-to-noise ratio (SNR) is so low that enhancing SNR of VSD has become important. In this study, we investigated the metal-enhanced fluorescence (MEF) effect on VSD imaging by fabricating nanoplasmonic resonance chip using gold nanorods (GNRs). To amplify the fluorescence signal we used polyelectrolyte layers to control the distance between metal nanoparticles and fluorophore. Cultured rat hippocampal neurons and di-8-ANEPPS, a widely used VSD, were used to test the nanoplasmonic resonance chip, and the maximum level of fluorescence signal was obtained when nine layers of polyelectrolyte spacer were used. The nanoplasmonic resonance chip with GNR showed the possibility of the improvement in voltage imaging of neurons and is expected to enhance the availability of neuronal activity imaging in the future.

Recent Applications of Point‑of‑Care Devices for Glucose Detection on the Basis of Stimuli‑Responsive Volume Phase Transition of Hydrogel

Nailong Gao,Hui You 한국바이오칩학회 2021 BioChip Journal Vol.15 No.1

Diabetes is a serious global disease that threatens more than 400 million people’s health. Therefore, timely detection of body’s glucose level becomes extremely important for control, diagnosis and treatment of diabetes. Based on the feature of stimuli-responsive volume phase transition of hydrogel materials, this review will provide a systematic summary of glucose detection devices in recent years, including hydrogel preparation methods based on glucose-sensitive pattern, detection mechanisms based on signal transduction, current and emerging devices based on different body fluids and discuss the challenge, prospect the future development trend in the end.

A Cost-effective Microdevice Bridges Microfluidic and Conventional in vitro Scratch / Wound-healing Assay for Personalized Therapy Validation

AnXiu Gao,YunLi Tian,ZhuanZhuan Shi,Ling Yu 한국바이오칩학회 2016 BioChip Journal Vol.10 No.1

Enhanced motility in malignant cell is one hallmark of tumor metastasis. The clinical reality is that each of us responds differently to treatment, driving a significant interest in the development of therapies that are “right” to the individual. A biomedical analytical tool with low-cost, sensitive and short assaytime is critical for personalized medicine. Herein, a cost-effective and user-friendly microfluidic device was developed for studying of cell migration. A two-step photolithography procedure was conducted to reveal microchannels and microchambers with different depth. The PDMS/glass slide hydride device was assembled between a polymethyl methacrylate (PMMA) clamp which can adjust the pressure imposed on the device to control the fluid communication between mainchambers, thus identical wound (cell-free space) with clear edge can be easily formed within channel without extra chemical, mechanical force, fluidic manipulation and sophisticated microstructure. Using this device, we evaluated the combinatory of BRAFV600E inhibitor vemurafenib and epidermal growth factor receptor (EGFR) inhibitor gefitinib in inhibiting of melanoma cell migration with only 20 μL cell consumption, highlighting its potential in assaying rare clinical biopsy for personalized medicine. In addition, the on-chip migration model followed strictly follow the principle of conventional in vitro scratch/wound healing assay, facilitating it is translation to biologist.

Single-Shot Light-Field Microscopy: An Emerging Tool for 3D Biomedical Imaging

김기수 한국바이오칩학회 2022 BioChip Journal Vol.16 No.4

3D microscopy is a useful tool to visualize the detailed structures and mechanisms of biomedical specimens. In particular, biophysical phenomena such as neural activity require fast 3D volumetric imaging because fluorescence signals degrade quickly. A light-field microscope (LFM) has recently attracted attention as a high-speed volumetric imaging technique by recording 3D information in a single-snapshot. This review highlighted recent progress in LFM techniques for 3D biomedical applications. In detail, various image reconstruction algorithms according to LFM configurations are explained, and several biomedical applications such as neuron activity localization, live-cell imaging, locomotion analysis, and single-molecule visualization are introduced. We also discuss deep learning-based LFMs to enhance image resolution and reduce reconstruction artifacts.

One-Step Homogeneous Immunoassay for the Detection of Influenza Virus Using Switching Peptide and Graphene Quencher

김홍래,봉지홍,김태훈,신승식,강민정,심원보,이도영,손동희,변재철 한국바이오칩학회 2022 BioChip Journal Vol.16 No.3

One-step homogeneous immunoassay was developed for detecting influenza viruses A and B (Inf-A and Inf-B) using the switching peptide H2. As the fluorescence-labeled switching peptide dissociated from the binding pocket of detection antibodies, the fluorescence signal could be directly generated by the binding of Inf-A and Inf-B without washing (i.e., one-step immunoassay). For the one-step homogeneous immunoassay with detection antibodies in solution, graphene was labeled with the antibodies as a fluorescence quencher. To test the feasibility of the homogeneous one-step immunoassay, the stability of the antibody complex with the switching peptide was evaluated under different pH and salt conditions. The one-step homogeneous immunoassay with switching peptide was conducted using influenza virus antigens in phosphate-buffered saline and real samples with inactivated Inf-A and Inf-B spiked in serum. Finally, the one-step homogeneous immunoassay results were compared with those of commercially available lateral flow immunoassays.

Separation of White Blood Cells in a Wavy Type Microfluidic Device Using Blood Diluted in a Hypertonic Saline Solution

Sanjay Mane,Vadiraj Hemadri,Siddhartha Tripathi 한국바이오칩학회 2022 BioChip Journal Vol.16 No.3

White blood cells (WBCs) provide crucial information pertaining to human health, and its separation from other blood constituents is imperative for blood-based diagnostics of various pathological conditions. However, efficient WBC separation and enrichment remain to be a challenge. We propose a novel mechanism of WBC separation in a microfluidic device using centrifugal forces, inertial forces, and diluted human blood prepared with hypertonic saline solution. Herein, a simple wavy type microchannel called the separation channel was designed to separate and enrich WBCs. Almost 88% of WBCs were separated with a purity of 83% with diluted blood, i.e., hematocrit (Hct) 2.8% prepared using a 10% hypertonic solution. In addition, the effect of hematocrit and flow rate on WBC separation is also reported in this work. The proposed microdevice can be used for enrichment and separation of WBCs and also develop a better understanding of the interactions amongst blood cells with altered properties.

Magnetic Nanochain-Based Smart Drug Delivery System with Remote Tunable Drug Release by a Magnetic Field

강병훈,신무광,한승민,오일영,김은정,박요셉,손혜영,강태준,정주연,허용민,함승주,임은경 한국바이오칩학회 2022 BioChip Journal Vol.16 No.3

Considerable attention is given to drug delivery technology that efficiently delivers appropriate levels of drug molecules to diseased sites with significant therapeutic efficacy. Nanotechnology has been used to develop various strategies for targeted drug delivery, while controlling the release of drugs because of its many benefits. Here, a delivery system was designed to control drug release by external magnetic fields using porous silica and magnetic nanoparticles. Magnetic nanochains (MNs) of various lengths (MN-1: 1.4 ± 0.8 μm, MN-2: 2.2 ± 1.1 μm, and MN-3: 5.3 ± 2.0 μm) were synthesized by controlling the exposure time of the external magnetic force in magnetic nanoaggregates (MNCs). Mesoporous silica-coated magnetic nanochains (MSMNs) (MSMN-1, MSMN-2, and MSMN-3) were prepared by forming a porous silica layer through sol–gel polymerization. These MSMNs could load the drug doxorubicin (DOX) into the silica layer (DOX-MSMNs) and control the release behavior of the DOX through an external rotating magnetic field. Simulations and experiments were used to verify the motion and drug release behavior of the MSMNs. Furthermore, a bio-receptor (aptamer, Ap) was introduced onto the surface of the DOX-MSMNs (Ap-DOX-MSMNs) that could recognize specific cancer cells. The Ap-DOX-MSMNs demonstrated a strong therapeutic effect on cancer cells that was superior to that of the free DOX. The potent ability of these MSMNs as an external stimulus-responsive drug delivery system was proven.

High-Performance Graphene FET Integrated Front-End Amplifier Using Pseudo-resistor Technique for Neuro-prosthetic Diagnosis

jatoth deepak naik,Pradeep Gorre,Naga Ganesh Akuri,Sandeep Kumar,Ala’aDdin Al-Shidaifat,송한정 한국바이오칩학회 2022 BioChip Journal Vol.16 No.3

A complex analysis of spike monitoring in neuro-prosthetic diagnosis demands a high-speed sub-nanoscale transistors with an advanced device technologies. This work reports the high performance of Graphene field-effect transistor (GFET) based front-end amplifier (FEA) design for the neuro-prosthetic application. The 9 nm Graphene FET device is optimized by characterization of transconductance and drain current towards high sensitivity and small factor. The proposed GFET-based FEA with pseudo-resistor technique demonstrates very high-input impedance in Tera-ohms that nullify the input leakage current. Here, gain-bandwidth product and noise optimization of GFET FEA enhances the overall gain with negligible noise. The proposed design operates at low voltage, further reduces the power consumption, and achieves less chip area in sub-nano size so it could be more suitable for implantable devices. The GFET-based FEA architecture achieves an action potential spike of 1.4 μV while the local field potentials spike of 1.8 mV. The proposed architecture is implemented in Advanced Design System using the design kit of the GFET process. Power consumption of 3.14 μW is observed with a supply voltage of 0.9 V. The simulated and experimental results of the proposed design achieve an input impedance of 2 TΩ with excellent noise performance over a wideband of 13.85 MHz. The proposed work demonstrates better neural activity sensing when compared to the state-of-the-artwork, which could be highly beneficial for future neuroscientists.

Inhibition of Non-specific Amplification in Loop-Mediated Isothermal Amplification via Tetramethylammonium Chloride

장민주,김상효 한국바이오칩학회 2022 BioChip Journal Vol.16 No.3

Loop-mediated isothermal amplification (LAMP) may be used in molecular and point-of-care diagnostics for pathogen detection. The amplification occurs under isothermal conditions using up to six primers. However, non-specific amplification is frequently observed in LAMP. Non-specific amplification has the potential to be triggered by forward and reverse internal primers. And the relatively low reaction temperature (55–65 °C) induces the secondary structure via primer–primer interactions. Primer redesign and probe design have been recommended to solve this problem. LAMP primers have strict conditions, such as Tm, GC contents, primer dimer, and distance between primers compared to conventional PCR primers. Probe design requires specialized knowledge to have high specificity for a target. In polymerase chain reaction (PCR), some chemicals or proteins are used for improving specificity and efficiency. Therefore, we hypothesized that additives can suppress the non-specific amplification. In this study, tetramethylammonium chloride (TMAC), formamide, dimethyl sulfoxide, Tween 20, and bovine serum albumin have been used as LAMP additives. In our study, TMAC was presented as a promising additive for suppressing non-specific amplification in LAMP.