As the fields of bionanotechnologies develop, it will become possible one day to use biological nanodevices such as nanorobots for in situ and real-time in vivo diagnosis and therapeutic intervention of specific targets. A prerequisite for designing and constructing wireless biological nanorobots is the availability of an electrical source which can be made continuously available in the operational biological environment (i.e. the human body). Several possible sources - temperature displacement, kinetic energy derived from blood flow, and chemical energy released from biological motors inside the body - have been designed to provide the electrical sources that can reliably operate in body. Researchers now report the construction of a 980-nm laser-driven photovoltaic cell that can provide a sufficient power output even when covered by thick biological tissue layers.