Lab-on-a-chip and Microarrays (Biochip): Miniaturizing Diagnostics and Analysis

Lab-on-a-chip and Microarrays (Biochip)

Lab-on-a-chip (LoC) refers to miniaturized devices built on a chip that can perform laboratory experiments and analysis. Also known as "micro-total analysis systems" (μ-TAS), LoCs integrate one or several laboratory functions on a single integrated circuit or microfabricated device no bigger than a few square centimeters. This drastically reduces reagents consumption and allows samples to be processed extremely quickly. Some key advantages of LoCs include portability, low sample/reagent volume requirements, fast analysis speeds, and potential for high-throughput testing.

How do LoCs Work?

LoCs leverage microfluidics technology to manipulate extremely small fluid volumes, typically on the scale of nanoliters or picoliters, through miniaturized fluidic chambers and channels etched onto the chip. Sample processing like mixing, separation, and reaction occur through controlled fluid movement and transport mechanisms. Microfabrication techniques allow manufacture of structures as small as 1 micrometer, enabling integration of various laboratory modules. Combining fluidics with electronics can help automate sample preparation, analysis and readout generation from minimal sample volumes.

Applications in Biology and Healthcare

Some areas where LoCs are being applied include point-of-care diagnostics, environmental monitoring, drug discovery and food safety testing. In healthcare, LoCs can perform rapid sample-to-answer tests for pathogens, proteins and DNA/RNA outside centralized laboratories. Portable LoC devices have been developed for detecting biomarkers related to cancer, HIV and infectious diseases directly from patient samples. Their small size makes LoCs ideal for testing in resource-limited settings. The defense, agriculture and food sectors also employ biosensor-integrated LoCs for applications like biothreat agent detection, genetic testing of plant/animal pathogens and allergen testing in food products respectively.

Introduction to Lab-On-A-Chip and Microarrays (Biochip)

Microarrays, also known as biochips, are collections of microscopic DNA spots arranged in orderly fashion on a solid surface like glass, silicon, nylon or microbeads. Each spot contains picomoles (10−12 moles) of a specific DNA sequence and their location is known, allowing for detection of target sequences in a biological sample. Depending on the assay, microarray spots may contain genes, SNPs, cDNA or oligonucleotides to enable analysis of gene expression, mutation detection or DNA fingerprinting. Microarrays are major tools for genomic and proteomic research as they allow massively parallel testing of large numbers of biomolecules simultaneously.

How do Microarrays Work?

In a basic microarray assay, fluorescently labeled DNA/RNA targets extracted from a test sample are pumped over the array surface. Through Watson-Crick base pairing, these targets will hybridize to their complementary probes/sequences printed on the chip. The array is then scanned with a laser to detect fluorescence at each spot - the strength of signal indicates degree of hybridization and hence expression level of that particular sequence. Microarrays thus generate quantitative expression profiles for thousands of sequences in a single experiment. Comparative genomic hybridization can also be performed to detect copy number changes between normal and diseased genomes.

Applications in Molecular Diagnostics and Research

Since their introduction in the 1990s, DNA microarrays have revolutionized genomic research by enabling profiling of genomes, transcriptomes and epigenomes at an unprecedented scale. In healthcare, clinical diagnostic microarrays can identify genetic mutations behind various disorders, screen for infectious agents and detect chromosomal abnormalities. Microarrays have also enabled major initiatives like The Cancer Genome Atlas for comprehensive molecular characterization of cancer. Other areas of application include toxicogenomics, analysis of alternative splicing and non-coding RNAs, genome-wide association studies and microbiome analysis. Commercial microarray platforms that are FDA approved for clinical use exist for various conditions such as cancer subtyping and infection diagnosis.

Fundamental Differences Between Lab-On-A-Chip And Microarrays (Biochip)

While Lab-On-A-Chip And Microarrays (Biochip) both deal with miniaturization and parallel analysis of biomolecules, they differ fundamentally in their designs and operation mechanisms.

LoCs are microfabricated devices that leverage microfluidics to transport and isolate analytes on one integrated platform, and usually enable fully automated multi-step processing of small sample volumes. Microarrays, on the other hand, are static devices where fluorescently-labeled targets are pumped over the surface for hybridization-based detection of gene sequences or other biomolecules.

LoCs are designed to perform complete laboratory experiments, mix samples, purify components and generate readouts - essentially serving as "labs-on-chips". Microarrays only perform detection assays and generate expression/sequencing data without requiring additional sample processing.

Finally, while LoCs involve real-time manipulation of picoliter volumes, microarrays work with microliter volumes through passive hybridization of pre-labeled samples. So LoCs represent more sophisticated lab devices whereas microarrays are focused detection tools.

Combining the Best of Both Worlds

Researchers are actively exploring approaches to combine the strengths of lab-on-a-chip and microarrays (biochip)  for development of next-generation precision diagnostic tools. Integrating microarray detection platforms into LoC devices would result in fully automated sample-to-answer systems capable of single-step pathogen identification, disease screening, toxicology testing and clinical decision support. Some challenges include optimizing microarray integration onto microfluidic circuits and ensuring sufficient hybridization efficiencies. Another exciting prospect is development of microarray-enhanced LoCs for applications like molecular pathology, non-invasive prenatal testing and cancer liquid biopsies. Overall, converging microfluidics with microarray detection holds tremendous promise for accelerating healthcare diagnostics in the years to come

 

Get more insights on lab-on-a-chip and microarrays (biochip)  

 

About Author:

Money Singh is a seasoned content writer with over four years of experience in the market research sector. Her expertise spans various industries, including food and beverages, biotechnology, chemical and materials, defense and aerospace, consumer goods, etc.

(https://www.linkedin.com/in/money-singh-590844163)