Biomaterials

Tissue engineering, drug delivery, design of biomolecules and biopolymers, biosensors, biomaterial mechanics, and laser spectroscopy are all the subjects of biomaterials research at Boston University. All of these areas have applications in the burgeoning health care field and involve faculty from various departments throughout BU’s College of Engineering and College of Arts and Sciences.

These interdisciplinary groups of scientists and engineers share facilities, work together under collaborative grants and publish their findings jointly.

Exciting developments over the last decade of materials-based technologies for diagnostics and therapeutic applications range from lab-on-a-chip devices to drug delivery systems to novel engineered tissues. Our group addresses the fundamental basic science underlying these technologies and also apply these technologies to real-world problems. Below are representative examples:

Biomedical Diagnostics and Detection: We are working in research areas related to diagnostics and detection such as contrast-enhanced MR- (Wong), ultrasound (Wong, Klapperich), and near-IR (Grinstaff, Erramilli) imaging, lab-on-a-chip (Klapperich), and single biomolecule detection in vitro and in vivo (Meller). Klapperich has been developing a suite of techniques for lab-on-a-chip technology7 (Fig. 2A) and have recently described a method of immobilizing silica particles in a porous polymer monolith (formed in situ) to form a microscale solid-phase extraction system which has been used to extract DNA from spiked human serum and total RNA from virus. Meller has been developing ultrasensitive methods for sensing nucleic acids, proteins and enzymes using functionalized nanopores and nanopore arrays8,9 (an emergent class of purely electronic single molecule sensors). In an array format this method has the capacity for ultra high throughput single molecule detection (see Figure 1 below).

I-V data shows extreme sensitivity to pH.

Figure 1: (A) Microfluidic chip. (B) Solid-state functionalized 10 nm nanopores (cartoons of coated moleclues overlaid over high resolution TEM images). Center panel: I-V data shows extreme sensitivity to pH.

Therapeutic Delivery Grinstaff and Wong have research projects in targeted drug delivery. The Grinstaff lab has developed functional polymer nanoparticlesto deliver paclitaxel to lymph nodes. The nanoparticles respond to a mildly acidic environment (endosome) by swelling to several times their original size, thereby disrupting the endosomal membrane and releasing the contents of the nanoparticle into the cytoplasm (see Figure 2 below).

300 nm)

Figure 2: (A) Nanoparticles (blue) thought to swell, release paclitaxel (red), and destabilize endosome. (nucleus: yellow) (B) TEM (bar: 300 nm)

Tissue Engineering:  Efforts span cardiac and vascular (Tien, Wong), skin and nerve (Klapperich), ophthalmic (Grinstaff), and orthopedic applications (Grinstaff, Klapperich, and Morgan)10,11, which benefit from biophysical studies (e.g. mucus and mucin (Bansil12)) and development of new materials and characterization techniques by Gevelber, Bansil, Grinstaff, Klapperich, Morgan, and Wong.

Wong uses various approaches to tissue-engineer small diameter (< 6 mm) vascular grafts (see Figure 3 below). Wong’s recent work on cell response on electrospun nanofibers fits well with studies by Gevelber, who is developing methods to dynamically control the electrospinning process.

Procedure for constructing a tubular construct from individual stacked cell sheets that are rolled around a mandrel.

Figure 3: Procedure for constructing a tubular construct from individual stacked cell sheets that are rolled around a mandrel.