What Is Bionanotechnology?

Bionanotechnology is the application of nanotechnology principles to biological systems, combining the fabrication and manipulation of structures at the 1–100 nanometer scale with the molecular machinery and recognition elements of living organisms. At this size regime, the distinction between engineered device and biological molecule narrows: proteins, nucleic acids, lipids, and engineered nanoparticles are all nanoscale objects that interact through the same physical forces. The field draws on biochemistry, biophysics, materials science, and electrical engineering, and its principal outputs span diagnostic tools, drug delivery vehicles, and molecular computing architectures.

Bionanotechnology is related to, but distinct from, nanobiotechnology. Nanobiotechnology uses nanotechnology tools to study biological systems; bionanotechnology uses biological structures and principles to build new functional devices. In practice, the boundary between these orientations is fluid, and most research groups operate in both directions simultaneously. The potential significance of the field was foreshadowed by Richard Feynman's 1959 lecture "There's Plenty of Room at the Bottom" and has since been developed through decades of scanning probe microscopy, protein engineering, and nucleic acid synthesis.

DNA Nanotechnology and Self-Assembly

DNA nanotechnology exploits the highly specific Watson-Crick base-pairing of deoxyribonucleic acid to direct the self-assembly of nanoscale structures with programmable geometry. Short synthetic DNA strands called oligonucleotides fold or hybridize according to their sequence, and by designing complementary sequences, researchers can assemble two- and three-dimensional lattices, boxes, cages, and dynamic machines that open or close in response to molecular triggers. DNA origami, introduced by Paul Rothemund in 2006, uses a long scaffold strand and hundreds of short staple strands to fold DNA into arbitrary shapes with sub-nanometer positional control. These structures serve as scaffolds for positioning proteins, quantum dots, and nanoparticles with precision inaccessible by conventional lithography. The Nature article on biological applications of DNA nanomaterials surveys current challenges and future directions across biosensing, drug delivery, and cellular imaging.

Nanoparticles in Biological Systems

Nanoparticles including gold nanoparticles, quantum dots, iron oxide nanoparticles, and lipid nanoparticles interact with biological environments in ways that depend critically on their size, shape, and surface chemistry. Gold nanoparticles absorb and scatter light at wavelengths determined by their surface plasmon resonance, making them useful as contrast agents for cellular imaging and as heat sources for photothermal cancer therapy. Iron oxide nanoparticles are superparamagnetic at sizes below about 20 nanometers and are used as contrast agents in magnetic resonance imaging and as magnetic carriers for targeted drug delivery. A study published in PMC on applications of nanoparticles in biology and medicine established that nanoparticles operating in the same size domain as proteins can achieve intimate interaction with cellular machinery while providing diagnostic and therapeutic functions simultaneously.

Bionanomaterials for Diagnostics and Therapeutics

Combining biological recognition molecules with nanoscale transducers produces biosensors of exceptional sensitivity. Antibody-functionalized gold nanoparticles can detect femtomolar concentrations of target antigens in lateral flow assays. Aptamer-gated mesoporous silica nanoparticles release drug cargo only in the presence of a specific molecular trigger, providing a spatially and temporally controlled release mechanism. Lipid nanoparticles, used commercially to deliver messenger RNA vaccines including the COVID-19 vaccines developed in 2020, protect nucleic acid cargo from enzymatic degradation and facilitate cellular uptake through membrane fusion. The NIH article on nanotechnology in biotechnology published in PMC details how these therapeutic nanostructures are engineered and characterized.

Applications

Bionanotechnology has applications in a range of fields, including:

• Targeted drug delivery using functionalized nanoparticles that accumulate preferentially in tumor tissue
• mRNA and gene therapy using lipid nanoparticle delivery vehicles
• Point-of-care diagnostics using nanoparticle-based lateral flow or electrochemical assays
• Medical imaging contrast enhancement with iron oxide and gold nanoparticle agents
• DNA-based molecular computing and information storage systems