Hassna R. Ramay
University of Washington
OsseointegrationComposite numberAnatomySelf-healing hydrogelsDrug carrierBiomedical engineeringPhalanxNuclear chemistryPathologyMicroscopySolubilityComposite materialFourier transform infrared spectroscopyRegeneration (biology)FetusChemistryPolymer chemistryMaterials scienceImmunohistochemistryScanning electron microscopeLactic acidGraftingNail (anatomy)AmputationGlucuronic acidLiberationApatiteOsteoblastSwellingBone tissueChitosanDrug deliveryDrugWound healingNano-GenipinCortical boneBiological propertyPorous scaffoldBone regenerationMicro particlesCompressive strengthChemical engineeringTissue engineeringPolymerPEG ratioBiochemistryHistologyPorosityDosage formCrystallographyCoacervateBiologyBovine serum albuminMicrostructureScaffoldNanofiberNanocompositeNumerical digitToughness
8Publications
7H-index
2,216Citations
Publications 8
Newest
#1Christopher H. Allan (UW: University of Washington)H-Index: 13
#2Philip Fleckman (UW: University of Washington)H-Index: 52
Last. John M. Clark (UW: University of Washington)H-Index: 24
view all 15 authors...
Regeneration of mammalian digit tips is well described; however, associated cellular or molecular events have not been studied in humans. We describe an in vitro human fetal model of response to digit tip amputation, and report expression of the transcription repressor Msx1 in the developing and regrowing human digit tip. Human fetal digits from specimens ranging from 53 to 117 days' estimated gestational age (EGA) were cultured in a defined serum-free medium with supplemented oxygen for time pe...
32 CitationsSource
#1Narayan Bhattarai (UW: University of Washington)H-Index: 36
#2Hassna R. Ramay (UW: University of Washington)H-Index: 7
Last. Miqin Zhang (UW: University of Washington)H-Index: 81
view all 4 authors...
Nanoparticles of ~10 nm in diameter made with chitosan or lactic acid-grafted chitosan were developed for high drug loading and prolonged drug release. A drug encapsulation efficiency of 92% and a release rate of 28% from chitosan nanoparticles over a 4-week period were demonstrated with bovine serum protein. To further increase drug encapsulation, prolong drug release, and increase chitosan solubility in solution of neutral pH, chitosan was modified with lactic acid by grafting D,L-lactic acid ...
106 CitationsSource
#1Zhensheng Li (UW: University of Washington)H-Index: 9
#2Hassna R. Ramay (UW: University of Washington)H-Index: 7
Last. Miqin Zhang (UW: University of Washington)H-Index: 81
view all 4 authors...
This paper reports the development of a biodegradable porous scaffold made from naturally derived chitosan and alginate polymers for bone tissue engineering. The scaffold has a 3-D interconnected porous structure and was fabricated through thermally induced phase separation. The mechanical test showed that the scaffold has compressive strength of 0.46 ± 0.02 MPa — about 4 times that of the pure chitosan scaffold. The cell-material interaction study indicated that osteoblast cells seeded on the c...
Source
#1Hassna R. RamayH-Index: 7
#2Zhensheng LiH-Index: 9
Last. Miqin ZhangH-Index: 81
view all 4 authors...
10 CitationsSource
#1Zhensheng Li (UW: University of Washington)H-Index: 9
#2Hassna R. Ramay (UW: University of Washington)H-Index: 7
Last. Miqin Zhang (UW: University of Washington)H-Index: 81
view all 5 authors...
A biodegradable scaffold in tissue engineering serves as a temporary skeleton to accommodate and stimulate new tissue growth. Here we report on the development of a biodegradable porous scaffold made from naturally derived chitosan and alginate polymers with significantly improved mechanical and biological properties as compared to its chitosan counterpart. Enhanced mechanical properties were attributable to the formation of a complex structure of chitosan and alginate. Bone-forming osteoblasts ...
943 CitationsSource
#1Narayan Bhattarai (UW: University of Washington)H-Index: 36
#2Hassna R. Ramay (UW: University of Washington)H-Index: 7
Last. Miqin Zhang (UW: University of Washington)H-Index: 81
view all 5 authors...
Thermosensitive polymer hydrogels that undergo a sol-to-gel transition in response to temperature changes are of great interest in therapeutic delivery and tissue engineering as injectable depot systems. A chitosan-based, injectable thermogel was prepared by grafting an appropriate amount of PEG onto the chitosan backbone and studied for drug release in vitro using bovine serum albumin (BSA) as a model protein. When more than ∼40 wt.% of PEG was grafted to chitosan chains via covalent bonding, t...
650 CitationsSource
#1Hassna R. Ramay (UW: University of Washington)H-Index: 7
#2Miqin Zhang (UW: University of Washington)H-Index: 81
Abstract A novel biodegradable nanocomposite porous scaffold comprising a β -tricalcium phosphate ( β -TCP) matrix and hydroxyl apatite (HA) nanofibers was developed and studied for load-bearing bone tissue engineering. HA nanofibers were prepared with a biomimetic precipitation method. The composite scaffolds were fabricated by a method combining the gel casting and polymer sponge techniques. The role of HA nanofibers in enhancing the mechanical properties of the scaffold was investigated. Comp...
501 CitationsSource
#1Hassna R. Ramay (UW: University of Washington)H-Index: 7
#2Miqin Zhang (UW: University of Washington)H-Index: 81
Abstract A new technique of combining the gel-casting and polymer sponge methods is introduced in this study to prepare macroporous hydroxyapatite scaffolds, which provides a better control over the microstructures of scaffolds and enhances their mechanical properties. With this technique, we were able to produce scaffolds with mechanical and structural properties that cannot be attained by either the polymer sponge or gel-casting method. The scaffolds prepared have an open, uniform and intercon...
618 CitationsSource