Antisense drugs are gene-based molecules that inhibit the synthesis of proteins (including proteins that cause specific diseases) by binding to the ribonucleic acids (RNAs) responsible for their formation. Specifically, these drugs are single-stranded short polymers of RNA or deoxyribonucleic acid (DNA), termed oligonucleotides, designed to contain part of the noncoding strand of messenger RNA (mRNA), which is a molecule involved in translating DNA into protein. Antisense medications are therefore capable of hybridizing with and inactivating the mRNA, preventing the associated gene from producing the unwanted protein. With their anticancer, antiviral, and anti-inflammatory therapeutic capacities, these drugs have been applied in the treatment of various genetic disorders and infections, including diabetes, rheumatoid arthritis, cytomegalovirus retinitis (a virally caused form of blindness that occurs often in AIDS patients), asthma, hypercholesterolemia (a genetic derangement of fat metabolism characterized by very high levels of cholesterol in the blood), and numerous cancers. Research is also being conducted on patients suffering from Parkinson's disease and Huntington's disease to determine whether antisense therapy can mitigate the effects of these conditions. See also: Biotechnology; Deoxyribonucleic acid (DNA); Disease; Gene; Genetic engineering; Oligonucleotide; Protein; Ribonucleic acid (RNA)

Biodegradable metals, also known as bioresorbable or bioabsorbable metals, are compatible with human tissues and degrade to nontoxic by-products. The most promising candidates for use as orthopedic and cardiovascular implants are alloys of magnesium, which biodegrade in 6–15 months, and alloys of iron, which biodegrade in 12–36 months. Both types of alloy degrade by corrosion—the oxidation and dissolution of the metals. See also: Alloy; Corrosion; Iron; Iron alloys; Magnesium; Magnesium alloys

In an application of green chemistry, researchers reported in the journal Biomaterials (April 2018) the caffeine-catalyzed synthesis of a new class of polymer gels for drug delivery and other biomedical applications. These caffeine-catalyzed gels (CCGs) are easy to make and are customizable in terms of their chemical and physical properties, such as their composition, shape, solvent sensitivity, drug release, and mechanical strength. The gels have potential to be consumed as chewable and easier to swallow drug-delivery systems. They contain a small amount of caffeine but were found to be safe in toxicity tests. See also: Biomedical engineering; Caffeine; Catalysis and catalysts; Citric acid; Drug delivery systems; Gel; Green chemistry; Polymer

CRISPR/Cas9 gene editing is a modern technique that targets specific stretches of genetic code and allows editing of deoxyribonucleic acid (DNA) at designated locations. It has been at the forefront of genetic research, providing scientists with the ability to undertake various genome-engineering projects, including opportunities for the modification of genes and the potential correction of mutations to prevent genetic diseases. However, the CRISPR (which stands for clustered regularly interspaced short palindromic repeats) genomic tool is limited by its precision. Specifically, the limiting factor is the DNA-cutting enzyme. The most commonly used enzyme is known as Cas9, but it only attaches to and targets a particular three-base sequence in the DNA that occurs in one-sixteenth of the human genome. This hampers the ability of researchers to carry out many applications that would entail editing of sequential segments of the DNA that occur more often. See also: CRISPR-based immunity in prokaryotes; CRISPR/Cas9 gene editing; CRISPR genome-editing methods against superbugs; Deoxyribonucleic acid (DNA); Enzyme; Gene; Genetic code; Genetic engineering; Genetics; Mutation

Mucus produced by the common garden snail (Helix aspersa) is green. The slime is not actually green in color but is “green” in terms of its environmentally friendly chemistry. It turns out that this snail’s mucus has chemical properties as a reducing agent for producing gold nanoparticles that promote wound healing and for use in other biomedical applications, according to researchers reporting in the journal Soft Matter (November 2020). The idea of using snail slime in medicine is not that farfetched, as snail slime was used by ancient Greeks to treat skin inflammation, and snail slime protein is currently used in cosmetics—although with the snootier name of “snail secretion filtrate hydrates”—for its skin-hydrating properties and to treat acne. See also: Gastropoda; Gold; Green chemistry; Inflammation; Nanoparticle; Skin; Skin disorders

Breast cancer is one of the most diagnosed cancers worldwide. If caught and treated early enough, the survival rate exceeds 90 percent. Unfortunately, survival can drop as low as 25 percent fairly quickly if detection occurs later in the progression of the disease. In the United States, women over the age of 50 are recommended to get routine screenings every two years, but more aggressive tumors can appear between screenings. Aside from physical examination, two of the most common screening methods are mammography (mammogram), which is x-ray based, and ultrasound. Whereas mammography is more sensitive for routine screenings of women over age 60, ultrasound typically has higher sensitivity for those under 45 years old because of higher breast tissue density. See also: Breast cancer and other breast disorders; Mammography; Radiology

CRISPR, or Clustered Regularly Interspaced Short Palindromic Repeats, is being applied extensively in genetic engineering. Using CRISPR–associated enzyme 9 (Cas9) and guide RNA (gRNA), scientists have the ability to utilize CRISPR to easily and accurately genetically modify organisms to contain, remove, or alter a selected gene sequence. There has been promising research suggesting that, due to CRISPR’s ability to edit the genome of an organism, CRISPR could be used to treat a variety of diseases and disorders in the human body—including cancer. In fact, scientists have already used CRISPR to treat certain types of cancers, such as leukemia and lung cancer. A new study indicates that CRISPR may also be the answer to a cure for endometrial cancer, which is responsible for the deaths of nearly 8000 women annually, according to the Washington University School of Medicine in St. Louis. See also: Cancer; CRISPR/Cas9 gene editing; Enzyme; Genetic engineering; Ribonucleic acid (RNA)