The field of ultrasound has expanded since the discovery of ultrasound
contrast agents (UCAs) from diagnostics to therapeutic use. UCAs are known as
microbubbles (MBs), which can be chemically and physically manipulated to improve
their therapeutic potential. MBs can be tailored to bind to specific diseased tissues and
act as carriers of different chemo-drugs and genetic materials. These engineered MBs
can behave differently to ultrasound intensities resulting in different cavitation methods.
Though the underlying mechanism is yet to be fully understood, there is evidence to
suggest that mechanical pore formation of cellular membranes allows for the temporary
uptake of drugs. The cavitation of MBs can induce temporary and reversible
enhancement in the permeability of both individual cells as well as the endothelium
including the blood brain barrier. There are too many side-effects and immune
responses to current cancer and diseased treatments. MBs protect the immunogenic
drugs from eliciting a detrimental response when delivered through the vasculature.
They also help reduce the drug dosage by improving drug targeting and drug response.
Thus, MBs can be used as vehicles for localized drug delivery and gene therapy
allowing us to further develop the potential of curing cancer and other diseases.
Keywords: Microbubbles, ultrasound, ultrasound contrast agent, chemotherapy,
adenovirus, polyethylene glycol, perfluropentane, phospholipid, sonoporation,
cavitation, Blood Brain Barrier (BBB), gene therapy, chemotherapy, DNA, RNA,
protein, siRNA, miRNA, drug delivery.
