Bone Regeneration from PLGA Micro-Nanoparticles

Table 2

Nano/microparticles systems to encapsulate GFs, mainly BMP2 growth factor. Most of them are in the microscopic scale and were used to be entrapped into scaffold of different characteristics. PVA has been the more used surfactant-stabilizer. It is possible to find both, encapsulation and surface adsorption of the growth factors with high-moderate efficiency. The use of heparin as stabilizer reduces significantly the initial burst release, favoring a sustained release in the time. The bioactivity of the GF was preserved in most of the systems and coencapsulation with other biomolecules seems to have a similar effect than the use of surfactants as stabilizers.

Polymers	Stabilizer	Size	Encapsulation; % EE	Release	Biological activity	Reference
PLGA	PVA	10–20 µm	Adsorbed rhBMP2	20 ng/mL of constant sustained release	Better bone formation after 8 weeks	Fu et al. 2013 [44]
PLGA	PVA	10–100 μm	rhBMP2-BSA; 69% (BMP)	Burst (20%); Sustained until 77% (28 days)	BMP2 molecules with bioactivity	Tian et al. 2012 [45]
PLGA 75 : 25	PVA	182 μm	82%	—	Good bone; defect repair outcomes within 8−12 weeks	Rodríguez-Évora et al. 2014 [46]
PLGA	PVA	228 μm	60,5%	30% initial burst. Slower release of 4% per week. After 8 weeks 60% released	No loss of bioactivity	Reyes et al. 2013 [47]
PLGA/PEG	No double emulsion synthesis	100–200 μm	Adsorbed BMP2	13% initial burst. Slower release of 0.01–8% per day. After 23 days 70% released	Substantial bone regeneration of the scaffold	Rahman et al. 2014 [48]
Different PLGA	PVA	20–100 μm	30% (uncapped PLGA); 90% (capped PLGA)	26–49% (1 day); Total after 2 weeks	No loss of bioactivity	Lupu-Haber et al. 2013 [49]
PLGA 75 : 25	PVA	5–125 μm	—	Initial burst 30% (1 day); Sustained 35 days	Higher volumes and surface area coverage of new bone	Wink et al. 2014 [50]
PLGA	Heparin	200–800 nm	Adsorbed BMP2; 94%	No initial burst. Sustained over 4 weeks	Significant reduction of the BMP2 dose for good bone formation	La et al. 2010 [51]
PLGA	Heparin- Poloxamer	160 nm	Adsorbed BMP2; 100%	Initial burst (4–7%) linear profile	Higher matrix mineralization of regenerated bone	Chung et al. 2007 [52]
PLGA	Heparin	100–250 nm	Adsorbed 94%	Initial burst 10% (1 day); 60% after 30 days	No loss of bioactivity; Efficacy of administration, amount 50-fold lower	Jeon et al. 2008 [53]
PLGA	PVA	~300 nm	80%	85% initial burst (1 day)	No loss of bioactivity	Yilgor et al. 2009 [54]
PLGA (in rings)	PVA	215 μm	66%	Moderate burst; Sustained release over 6 weeks	60% of calvaria defect were healed	Rodríguez-Évora et al. 2013 [55]
PLGA-Poloxamer 188 Blend	Poloxamer	150 nm	FGF-BSA-Heparin; 60–80%	40% initial burst (1 day), 60% (30 days)	No loss of bioactivity	d’Angelo et al. 2010 [56]
Different PLGA polymers	PVA	μm order	rhBMP2 adsorption; 40–75%	20–80% initial burst (1 day)	—	Schrier et al. 2001 [57]
PLGA/PEG	PVA	37–67 μm	72–99%	33% initial burst (1 day)	Little loss of bioactivity	Lochmann et al. 2010 [58]
PLGA/PLGA-PEG-PLGA	PVA	100 μm	HSA-BMP2; 60%	70% initial burst (1 day)	No loss of bioactivity	White et al. 2013 [59]
PLGA	PVA	100–1000 nm	Α-1-antitrypsin; 90%	30% initial burst (1 day); 50% after 24 days	Biological activity was preserved using BSA and β-cyclodextrine.	Pirooznia et al. 2012 [60]