Recent Trends and Innovations in Bead-Based Biosensors for Cancer Detection.

Demand is strong for sensitive, reliable, and cost-effective diagnostic tools for cancer detection. Accordingly, bead-based biosensors have emerged in recent years as promising diagnostic platforms based on wide-ranging cancer biomarkers owing to the versatility, high sensitivity, and flexibility to perform the multiplexing of beads. This comprehensive review highlights recent trends and innovations in the development of bead-based biosensors for cancer-biomarker detection. We introduce various types of bead-based biosensors such as optical, electrochemical, and magnetic biosensors, along with their respective advantages and limitations. Moreover, the review summarizes the latest advancements, including fabrication techniques, signal-amplification strategies, and integration with microfluidics and nanotechnology. Additionally, the challenges and future perspectives in the field of bead-based biosensors for cancer-biomarker detection are discussed. Understanding these innovations in bead-based biosensors can greatly contribute to improvements in cancer diagnostics, thereby facilitating early detection and personalized treatments.

Photonic crystal enhanced immunofluorescence biosensor integrated with a lateral flow microchip: Toward rapid tear-based diabetic retinopathy screening.

Diabetic retinopathy (DR) has accounted for major loss of vision in chronic diabetes. Although clinical statistics have shown that early screening can procrastinate or improve the deterioration of the disease, the screening rate remains low worldwide because of the great inconvenience of conventional ophthalmoscopic examination. Instead, tear fluid that contains rich proteins caused by direct contact with eyeballs is an ideal substitute to monitor vision health. Herein, an immunofluorescence biosensor enhanced by a photonic crystal (PhC) is presented to handle the trace proteins suspended in the tear fluid. The PhC was constructed by self-assembled nanoparticles with a thin layer of gold coated on top of it. Then, the PC substrate was conjugated with antibodies and placed in a microchannel. When the capillary-driven tear sample flew over the PC substrate, the immunoassay enabled the formation of a sandwich antibody-antigen-antibody configuration for PhC-enhanced immunofluorescence. The use of PhC resulted in a concentration enhancement of more than tenfold compared to non-PhC, while achieving an equivalent signal intensity. The limit of detection for the target biomarker, lipocalin-1 (LCN-1), reached nearly 3 µg/ml, and the turnaround time of each detection was 15 min. Finally, a preclinical evaluation was conducted using ten tear samples. A clear trend was observed, showing that the concentrations of LCN-1 were at least twofold higher in individuals with chronic diabetes or DR than in healthy individuals. This trend was consistent with their medical conditions. The results provided a direct proof-of-concept for the proposed PhC biosensor in rapid tear-based DR screening.

Using Sankey diagrams to explore the trend of article citations in the field of bladder cancer: Research achievements in China higher than those in the United States.

BACKGROUND: Urology authors are required to evaluate research achievements (RAs) in the field of bladder cancer (BC). However, no such bibliometric indices were appropriately applied to quantify the contributions to BC in research. In this study, we examined 3 questions: whether RAs in China are higher than those in the United States, how the Sankey-based temporal bar graph (STBG) may be applied to the analysis of the trend of article citations in the BC field, and what subthemes were reflected in China's and the United States' proportional counts in BC articles. METHODS: Using the PubMed search engine to download data, we conducted citation analyses of BC articles authored by urology scholars since 2012. A total of 9885 articles were collected and analyzed using the relative citations ratios (RCRs) and the STBG. The 3 research goals were verified using the RCRs, the STBG, and medical subject headings (MesH terms). The choropleth map and the forest plot were used to 1 highlight the geographical distributions of publications and RCRs for countries/regions and 2 compare the differences in themes (denoted by major MeSH terms on proportional counts using social network analysis to cluster topics) between China and the United States. RESULTS: There was a significant rise over the years in RCRs within the 9885 BC articles. We found that the RCRs in China were substantially higher than those in the United States since 2017, the STBG successfully explored the RCR trend of BC articles and was easier and simpler than the traditional line charts, area plots, and TBGs, and the subtheme of genetics in China has a significantly higher proportion of articles than the United States. The most productive and influential countries/regions (denoted by RCRs) were {Japan, Germany, and Italy} and {Japan, Germany, New York}, respectively, when the US states and provinces/metropolitan cities/areas in China were separately compared to other countries/regions. CONCLUSIONS: With an overall increase in publications and RCRs on BC articles, research contributions assessed by the RCRs and visualized by the STBGs are suggested for use in future bibliographical studies.

Developing Rapid Antimicrobial Susceptibility Testing for Motile/Non-Motile Bacteria Treated with Antibiotics Covering Five Bactericidal Mechanisms on the Basis of Bead-Based Optical Diffusometry.

Rapid antimicrobial susceptibility testing (AST) is an effective measure in the treatment of infections and the prevention of bacterial drug resistance. However, diverse antibiotic types and bacterial characteristics have formed complicated barriers to rapid diagnosis. To counteract these limitations, we investigated the interactions between antibiotic-treated bacteria and functionalized microbeads in optical diffusometry. The conjugation with bacteria increased the effective microbead complex size, thereby resulting in a temporal diffusivity change. The yielded data were sorted and analyzed to delineate a pattern for the prediction of antimicrobial susceptibility. The outcome showed that a completed rapid AST based on the trend of microbead diffusivity could provide results within 3 h (2 h measurement + 1 h computation). In this research, we studied four bacterial strains, including Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus aureus, and six antibiotics. Despite the different inhibitory effects caused by various antibiotics, similar trends in diffusivity alteration for all susceptible and resistant cases in the last 40 min of the 2-h measurement period were deduced. In addition, the AST results obtained using optical diffusometry showed good agreement with those acquired from the commercial instrument and conventional culture methods. Finally, we conducted a single-blinded clinical test, and the sensitivity, specificity, and accuracy of the system reached 92.9%, 91.4%, and 91.8%, respectively. Overall, the developed optical diffusometry showcased rapid AST with a small sample volume (20 µL) and low initial bacterial count (105 CFU/mL). This technique provided a promising way to achieve early therapy against microbial diseases in the future.

Nifedipine Exacerbates Lipogenesis in the Kidney via KIM-1, CD36, and SREBP Upregulation: Implications from an Animal Model for Human Study.

Dysregulation of fatty acid oxidation and accumulation of fatty acids can cause kidney injury. Nifedipine modulates lipogenesis-related transcriptional factor SREBP-1/2 in proximal tubular cells by inhibiting the Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) pathway in vitro. However, the mechanisms by which nifedipine (NF) modulates lipotoxicity in vivo are unclear. Here, we examined the effect of NF in a doxorubicin (DR)-induced kidney injury rat model. Twenty-four Sprague-Dawley rats were divided into control, DR, DR+NF, and high-fat diet (HFD) groups. The DR, DR+NF, and HFD groups showed hypertension and proteinuria. Western blotting and immunohistochemical analysis showed that NF significantly induced TNF-α, CD36, SREBP-1/2, and acetyl-CoA carboxylase expression and renal fibrosis, and reduced fatty acid synthase and AMPK compared to other groups (p < 0.05). Additionally, 18 patients with chronic kidney disease (CKD) who received renal transplants were enrolled to examine their graft fibrosis and lipid contents via transient elastography. Low-density lipoprotein levels in patients with CKD strongly correlated with lipid contents and fibrosis in grafted kidneys (p < 0.05). Thus, NF may initiate lipogenesis through the SREBP-1/2/AMPK pathway and lipid uptake by CD36 upregulation and aggravate renal fibrosis in vivo. Higher low-density lipoprotein levels may correlate with renal fibrosis and lipid accumulation in grafted kidneys of patients with CKD.

Culture-free detection of methicillin-resistant Staphylococcus aureus by using self-driving diffusometric DNA nanosensors.

The rapid and robust detection of infectious bacteria is vital in sepsis treatment because of their ability to reveal multi-drug resistance. This study presents culture-free and self-driving DNA nanosensors by combining diffusometry and oligonucleotide probes to rapidly detect a lethal superbug, methicillin-resistant Staphylococcus aureus (MRSA). The DNA nanosensors were synthesized with conjugated fluorescent nanobeads and designed oligonucleotide probes that can recognize the target sequences on MRSA's genomic DNA. The high selectivity and specificity of this binding ensure the accuracy of detection. A DNA fragment tagged with gold nanoparticles (AuNPs) was attached to the same MRSA single-stranded DNA (ssDNA) to form a sandwiched configuration. The protrusive AuNPs surrounding the nanobeads decreased the diffusivity of the complexed nanobeads by increasing the bead size. Accordingly, diffusivity was inversely proportional to the concentration of the target MRSA ssDNA. Each measurement required only 10 s. An optimal limit of detection of 10 pM was achieved. This study successfully developed DNA nanosensors based on diffusometry for the rapid and robust detection of target superbugs and unknown pathogenic microorganisms.

Therapeutic benefit of second-look transurethral resection of bladder tumors for newly diagnosed T1 bladder cancer: a single-center experience.

PURPOSE: In recent years, second-look transurethral resection of bladder tumors (TURBT) has been recommended for patients with stage T1 bladder cancer after the initial TURBT for restaging and deciding the subsequent treatment. However, we believe that second-look TURBT has therapeutic benefits, such as low incidence of recurrence and progression. Therefore, we compare the differences in long-term outcome between patients who did and did not accept second-look TURBT for stage T1 bladder cancer. METHODS: We assessed 504 patients diagnosed with urothelial carcinoma who underwent initial TURBT between January 2012 and December 2016 at a single medical center; of these patients, 177 were diagnosed with T1 bladder cancer during the initial TURBT, and we excluded no muscle from the specimen in the initial TURBT. The patients were categorized into groups 1 and 2 based on the acceptance of second-look TURBT, which was performed within 4-14 weeks after the initial TURBT. Group 1 underwent second-look TURBT, but group 2 did not. Both groups were followed-up for recurrence-free survival (RFS) and progression-free survival (PFS), and the risk factors for recurrence and progression were analyzed. RESULTS: In total, 93 (52.5%) patients in group 1 underwent second-look TURBT, and 84 (47.5%) in group 2 did not. The 2-year RFS rates were 74.6% and 60.0% and the PFS rates were 91.2% and 87.5% in groups 1 and 2, respectively. CONCLUSION: This study demonstrated higher recurrence-free and progression-free survival rates for patients who underwent second-look TURBT. This result emphasizes the importance of second-look TURBT in stage T1 bladder cancer not only for restaging but also for therapeutic benefit.

Label-Free Monitoring of Microorganisms and Their Responses to Antibiotics Based on Self-Powered Microbead Sensors.

Rapid detection of bacteria and their susceptibility to specific antibiotics plays a vital role in microbial infection treatments. Antimicrobial susceptibility testing (AST) is a common measure to select effective drugs. However, the conventional practices, such as broth dilution, E-test, and disk diffusion, in clinical applications require a long turnaround time (∼3 days), thereby compromising treatments and increasing mortality. This study presents self-powered sensors for on-site microorganism monitoring and rapid AST based on functionalized microbeads. The microbead sensors are driven by Brownian motion, rendering external power unnecessary. Fluorescent microbeads ( dp = 2 µm) were coated with vancomycin to capture bacteria. The growth and responses of Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus under antibiotic treatment were evaluated. The method showed stable selective binding despite the presence of some interferential substances, such as proteins and cells. Diffusivity change was strongly related to bacterial concentration. Accordingly, the diffusivity values of microbeads bound with motile and nonmotile bacteria exhibited specific patterns because of extra motility from microbes and increased particle diameter. Only a drop of microbead-bacteria suspension (∼5 µL) was needed in a microchip for each measurement. The microchip provided a steady environment for measurement over a few hours. By distinguishing the slope of the last four data points in the temporal diffusivity curve, bacterial susceptibility or resistance to specific antibiotics could be determined within a time frame of 2 h. The study provides insights into saving more lives by using a fast and robust AST technique in future clinical practice.

Simultaneous and quantitative monitoring of co-cultured Pseudomonas aeruginosa and Staphylococcus aureus with antibiotics on a diffusometric platform.

Successful treatments against bacterial infections depend on antimicrobial susceptibility testing (AST). However, conventional AST requires more than 24 h to obtain an outcome, thereby contributing to high patient mortality. An antibiotic therapy based on experiences is therefore necessary for saving lives and escalating the emergence of multidrug-resistant pathogens. Accordingly, a fast and effective drug screen is necessary for the appropriate administration of antibiotics. The mixed pathogenic nature of infectious diseases emphasizes the need to develop an assay system for polymicrobial infections. On this basis, we present a novel technique for simultaneous and quantitative monitoring of co-cultured microorganisms by coupling optical diffusometry with bead-based immunoassays. This simple integration simultaneously achieves a rapid AST analysis for two pathogens. Triple color particles were simultaneously recorded and subsequently analyzed by functionalizing different fluorescent color particles with dissimilar pathogen-specific antibodies. Results suggested that the effect of the antibiotic, gentamicin, on co-cultured Pseudomonas aeruginosa and Staphylococcus aureus was effectively distinguished by the proposed technique. This study revealed a multiplexed and time-saving (within 2 h) platform with a small sample volume (~0.5 µL) and a low initial bacterial count (50 CFU per droplet, ~105 CFU/mL) for continuously monitoring the growth of co-cultured microorganisms. This technique provides insights into timely therapies against polymicrobial diseases in the near future.

Dendritic Cell-Specific Transmembrane Protein (DC-STAMP) Regulates Osteoclast Differentiation via the Ca2+ /NFATc1 Axis.

DC-STAMP is a multi-pass transmembrane protein essential for cell-cell fusion between osteoclast precursors during osteoclast (OC) development. DC-STAMP-/- mice have mild osteopetrosis and form mononuclear cells with limited resorption capacity. The identification of an Immunoreceptor Tyrosine-based Inhibitory Motif (ITIM) on the cytoplasmic tail of DC-STAMP suggested a potential signaling function. The absence of a known DC-STAMP ligand, however, has hindered the elucidation of downstream signaling pathways. To address this problem, we engineered a light-activatable DC-STAMP chimeric molecule in which light exposure mimics ligand engagement that can be traced by downstream Ca2+ signaling. Deletion of the cytoplasmic ITIM resulted in a significant elevation in the amplitude and duration of intracellular Ca2+ flux. Decreased NFATc1 expression in DC-STAMP-/- cells was restored by DC-STAMP over-expression. Multiple biological phenotypes including cell-cell fusion, bone erosion, cell mobility, DC-STAMP cell surface distribution, and NFATc1 nuclear translocation were altered by deletion of the ITIM and adjacent amino acids. In contrast, mutations on each of the tyrosine residues surrounding the ITIM showed no effect on DC-STAMP function. Collectively, our results suggest that the ITIM on DC-STAMP is a functional motif that regulates osteoclast differentiation through the NFATc1/Ca2+ axis. J. Cell. Physiol. 232: 2538-2549, 2017. © 2016 Wiley Periodicals, Inc.

Detection of low-abundance biomarker lipocalin 1 for diabetic retinopathy using optoelectrokinetic bead-based immunosensing.

Early diagnosis of diabetic retinopathy (DR) is vital but challenging. DR is a common complication and a major cause of vision loss in patients with diabetes mellitus. Without appropriate medical intervention, visual impairment may become a great burden to our healthcare system. In clinical practice, the current diagnostic methods, such as fluorescence angiography and optical coherence tomography, remain constrained by non-quantitative examinations and individual ophthalmologists' experiences. Late diagnosis often prevents early treatment. To address the constraints on current diagnostics, this study developed an optoelectrokinetic bead-based immunosensing technique for detecting lipocalin 1 (LCN1), a DR biomarker. The concentration level of LCN1 in the tears of DR patients increases with DR severity. The immunoassay was dependent on the formation of sandwiched immunocomplexes on the particles. A secondary antibody labeled with dyes/quantum dots (QDs) was used to visualize the presence of the target antigens. Rapid electrokinetic patterning (REP), an optoelectrokinetic technique, was used to dynamically enhance the fluorescent signal by concentrating the modified particles. The limit of detection (LOD) of the technique could reach 110pg/mL. Only 1.5µL of a sample fluid was required for the measurement. Our results showed that highly sensitive and improved LOD is subjected to particle stacking, small particle size, and compact cluster. By labeling different particle sizes with dyes/QDs for LCN1 and TNF-α, we successfully used REP to detect the two DR biomarkers on the same platform. The development of an optoelectrokinetic bead-based immunosensing technique can provide new insights into diagnosing other low-abundance diseases in the future.

Rapid Bead-Based Antimicrobial Susceptibility Testing by Optical Diffusometry.

This study combined optical diffusometry and bead-based immunoassays to develop a novel technique for quantifying the growth of specific microorganisms and achieving rapid AST. Diffusivity rises when live bacteria attach to particles, resulting in additional energy from motile microorganisms. However, when UV-sterilized (dead) bacteria attach to particles, diffusivity declines. The experimental data are consistent with the theoretical model predicted according to the equivalent volume diameter. Using this diffusometric platform, the susceptibility of Pseudomonas aeruginosa to the antibiotic gentamicin was tested. The result suggests that the proliferation of bacteria is effectively controlled by gentamicin. This study demonstrated a sensitive (one bacterium on single particles) and time-saving (within 2 h) platform with a small sample volume (~0.5 µL) and a low initial bacteria count (50 CFU per droplet ~ 105 CFU/mL) for quantifying the growth of microorganisms depending on Brownian motion. The technique can be applied further to other bacterial strains and increase the success of treatments against infectious diseases in the near future.

A bead-based fluorescence immunosensing technique enabled by the integration of Förster resonance energy transfer and optoelectrokinetic concentration.

Bead-based immunosensing has been growing as a promising technology in the point-of-care diagnostics due to great flexibility. For dilute samples, functionalized particles can be used to collect dispersed analytes and act as carriers for particle manipulation. To realize rapid and visual immunosensing, Förster resonance energy transfer (FRET) was used herein to ensure only the diabetic biomarker, lipocalin 1, to be detected. The measurement was made in an aqueous droplet sandwiched between two parallel plate electrodes. With an electric field and a focused laser beam applying on the microchip simultaneously, the immunocomplexes in the droplet were further concentrated to enhance the FRET fluorescent signal. The optoelectrokinetic technique, termed rapid electrokinetic patterning (REP), has been proven to be excellent in dynamic and programmable particle manipulation. Therefore, the detection can be complete within several tens of seconds. The lower detection limit of the REP-enabled bead-based diagnosis reached nearly 5 nM. The combinative use of FRET and the optoelectrokinetic technique for the bead-based immunosensing enables a rapid measure to diagnose early stage diseases and dilute analytes.

A multivariable logistic regression equation to evaluate prostate cancer.

BACKGROUND/PURPOSE: A possible means of decreasing prostate cancer mortality is through improved early detection. We attempted to create an equation to predict the likelihood of having prostate cancer. METHODS: Between January 2005 and May 2008, patients who received prostate biopsies were retrospective evaluated. The relationship between the possibility of prostate cancer and the following variables were evaluated: age; serum prostate specific antigen (PSA) level, prostate volume, numbers of prostatic biopsies, digital rectal examination (DRE) findings, and the presence of hypoechoic nodule under transrectal ultrasonography. RESULTS: A multivariate regression model was created to predict the possibility of having prostate cancer, and a receiver-operating characteristic (ROC) curve was drawn based on the predictive scoring equation. Using a predictive equation, P=1/(1-e(-x)), where X=-4.88,+1.11 (if DRE positive),+0.75 (if hypoechoic nodule of prostate present),+1.27 (when 7